220-1202 — CompTIA A+ Core 2 Cheat Sheet

Cheat sheet: exam-prep reference for CompTIA A+ Core 2 (220-1202): operating systems, security, troubleshooting, and operational procedures.

This independent Cheat Sheet is for candidates preparing for the CompTIA A+ Core 2 (220-1202) exam. Use it to review high-yield operating system, security, troubleshooting, and operational procedure decisions quickly.

Use the tables for a quick pre-exam check. Expand a topic’s notes for explanations, examples, and additional distinctions.

Scope and study context

Core 2 is largely about working safely and professionally with operating systems, users, security settings, software problems, endpoint protection, and support procedures. The exam often rewards practical judgment: choosing the next best step, identifying the most likely cause, and applying a standard troubleshooting or security process without overcorrecting.

Use CompTIA’s current exam objectives as your scope authority. This page is IT Mastery practice support, not an official CompTIA resource.

Core 2 Exam Focus Map

AreaBe ready to doCommon exam trap
Operating systemsChoose installation methods, Windows tools, command-line utilities, recovery options, and OS featuresConfusing Settings, Control Panel, MMC snap-ins, and command-line repair tools
SecurityApply least privilege, authentication, malware removal, device hardening, wireless security, and data handlingTreating encryption, MFA, antivirus, or backups as complete security by themselves
Software troubleshootingDiagnose OS, application, browser, update, mobile, and network symptomsJumping to reinstall before checking logs, updates, services, permissions, and recent changes
Operational proceduresFollow safety, documentation, change management, professionalism, backup, and incident handling practicesSkipping documentation, user communication, or verification after a fix

Operating Systems Cheat Sheet

Installation and Deployment Choices

ScenarioChooseWhy
New device or unrecoverable OSClean installationRemoves previous OS state; requires data backup and app reinstall
Preserve apps, files, and settings when supportedIn-place upgradeFaster migration path, but carries over some misconfigurations
Many identical systemsImage deploymentConsistent baseline; often paired with unattended setup and post-deployment updates
Boot over network for imaging/installPXE/network bootUseful for enterprise deployment; requires network support
Need to reinstall while keeping user filesReset/refresh/recovery optionFaster than manual rebuild; still verify backup first
Test multiple OS versionsDual boot/multibootSeparate OS environments; bootloader and partition planning matter
Automated installUnattended installationUses answer/config files to reduce technician interaction
Repair boot or system filesRecovery environment/repair installUse before destructive reinstall when user data matters
Notes and examples

Windows Edition and Feature Selection

Feature availability can vary by Windows release and edition. For exam decisions, focus on the feature category.

NeedTypical edition directionNotes
Basic home useHome-class editionLimited business management features
Domain join, Group Policy, business managementPro/Business-class editionCommon small business choice
Enterprise policy control, advanced security, large-scale managementEnterprise/Education-class editionUsually centrally managed
BitLocker managementBusiness-class editionsDevice encryption may exist separately; know BitLocker is the full management feature
Remote Desktop hostBusiness-class editionsRemote Desktop client is broader than host support
Hypervisor featuresBusiness-class editionsAlso requires hardware virtualization support
Local users/groups managementBusiness-class editionsHome systems may use simplified account management

File Systems, Partitioning, and Boot Modes

ItemBest useExam notes
NTFSWindows internal drivesSupports permissions, encryption features, compression, large files
FAT32Broad compatibility, removable mediaLimited compared with modern file systems; not ideal for large files
exFATLarge removable media across OSsGood for USB drives shared across Windows/macOS
APFSModern macOS storageUsed by current macOS systems
ext4Common Linux storageStandard Linux file system choice
GPTModern disks, UEFI systemsPreferred for modern Windows deployments
MBRLegacy boot environmentsLegacy compatibility; avoid unless required
UEFIModern firmwareSupports Secure Boot and modern boot workflows
BIOS/legacyOlder firmwareMay be required for older OS or hardware
Secure BootPrevent unsigned bootloadersCan block some recovery media or alternate OS installs
TPMHardware-backed securityUsed by features such as device encryption and measured boot

Windows System Locations and Variables

Path or variablePurposeTrap
C:\WindowsWindows OS filesDo not casually edit or delete
C:\Windows\System32Core system binariesOn 64-bit Windows, System32 contains 64-bit binaries
C:\Windows\SysWOW6432-bit compatibility binariesName is counterintuitive
C:\Program Files64-bit application install pathApp architecture matters
C:\Program Files (x86)32-bit application install pathSeen on 64-bit Windows
C:\Users\usernameUser profileIncludes Desktop, Documents, AppData
%USERPROFILE%Current user profile variableUseful in scripts and paths
%TEMP%Temporary filesCan be cleared carefully during troubleshooting
%APPDATA%Roaming app dataUser-specific application settings
%LOCALAPPDATA%Local app dataNot intended to roam between devices

Windows editions and feature awareness

Know which features are associated with business-oriented Windows environments. Questions may ask why a feature is unavailable or which edition/configuration is appropriate.

Feature/categoryReview point
Domain or enterprise managementBusiness editions are commonly used where centralized identity and policy management are needed
BitLocker-style disk encryptionCommonly associated with protecting data at rest; know recovery-key implications
Remote Desktop host capabilityDo not confuse being able to connect outward with accepting inbound remote desktop sessions
Group PolicyCentralized configuration in managed environments; local policy affects one machine
Update controlsEnterprise environments may use staged updates, maintenance windows, and rollback planning

Installation and deployment choices

MethodUse when…Watch for…
Clean installationStarting fresh, replacing corrupted OS, repurposing deviceData wipe risk; backup first
Upgrade installationKeeping apps/data while moving to a newer supported OSCompatibility checks matter
Repair/in-place repairOS components are damaged but user environment should be preservedNot a substitute for backup
Image deploymentStandardizing many machinesDrivers, licensing, naming, domain identity, post-deployment updates
Recovery/resetReturning a malfunctioning system to working stateUnderstand keep-files vs remove-everything style choices
Network/PXE deploymentDeploying over the networkRequires network boot support and deployment infrastructure

File systems and storage concepts

File system/conceptHigh-yield point
NTFSWindows permissions, encryption/compression features, large file support
FAT32Broad compatibility but file size and feature limitations
exFATUseful for removable media and cross-platform exchange
ext familyCommon in Linux environments
APFSModern macOS file system
PartitionLogical division of a physical disk
MBR vs GPTPartitioning schemes; GPT is common on modern UEFI systems
Basic vs dynamic-style storageKnow that advanced volume features add complexity and recovery considerations

Boot and recovery decision table

SymptomConsider firstUseful tools/actions
Windows fails after driver updateBad driver or updateSafe Mode, rollback driver, uninstall update, System Restore/recovery tools
Repeated startup repair loopBoot files, disk, update failure, corruptionStartup Repair, command-line repair, disk diagnostics, restore/reset
Blue screen after new hardwareDriver, firmware, incompatible hardwareRemove device, update/rollback driver, check vendor support
Slow bootStartup apps, services, disk health, malware, updatesTask Manager startup tab, Services, Event Viewer, disk checks
User cannot sign inPassword, account lockout, profile corruption, domain connectivityVerify credentials, network, account status, local admin recovery path
“Operating system not found”Boot order, missing bootloader, failed diskBIOS/UEFI boot order, recovery media, disk diagnostics

Windows Tools and Where to Use Them

ToolUse whenHigh-yield notes
Settings appModern Windows configurationFirst stop for user-facing configuration
Control PanelLegacy/admin settingsStill appears in exam scenarios
Device ManagerDriver/device stateDisable, update, roll back, uninstall devices
Disk ManagementPartitions, volumes, drive lettersNot for deep file repair; use chkdsk for file system checks
ServicesStart/stop/configure servicesStartup type can be Automatic, Manual, Disabled
Task ManagerProcesses, startup apps, performance snapshotQuick triage for high CPU/RAM/disk
Resource MonitorMore detailed resource usageUseful for disk/network/process correlation
Performance MonitorCounters and long-term performance trackingMore detailed than Task Manager
Event ViewerLogs for system, security, application eventsCheck timestamps around the reported issue
Task SchedulerScheduled jobs and triggersMalware and admin scripts may persist here
System ConfigurationBoot and startup troubleshootingSafe boot and service isolation scenarios
Registry EditorLow-level configuration databaseBack up before edits; wrong edits can break Windows
Local Users and GroupsLocal account/group managementNot the same as domain account management
Local Security PolicyPassword, audit, and local security settingsLocal-only unless overridden by domain policy
Group Policy EditorPolicy settingsDomain Group Policy usually overrides local policy
Windows Defender FirewallHost firewall rulesCheck profile: domain, private, public
Windows SecurityAntivirus, threat protection, device securityCentral security dashboard
BitLocker managementFull-volume encryptionProtects data at rest, not data after login
Windows UpdateOS and driver updatesFailed updates often need logs, disk space, services
System RestoreRoll back system stateDoes not replace user data backup
Backup/File HistoryUser file recoveryVerify restore capability, not just backup existence
Recovery EnvironmentStartup repair, reset, restore, command promptUse for boot failures and offline repairs

Command-Line Reference

Windows Commands

CommandPrimary useExample exam clue
ipconfigShow IP configurationVerify address, gateway, DNS
ipconfig /allDetailed network configurationMAC address, DHCP, DNS servers
ipconfig /release and ipconfig /renewRenew DHCP leaseAPIPA or stale DHCP lease
ipconfig /flushdnsClear DNS resolver cacheWebsite resolves incorrectly on one PC
pingBasic connectivity testTest loopback, gateway, remote host
tracertTrace network pathDetermine where routing fails
nslookupDNS query testingConfirm name resolution
netstatShow network connectionsSuspicious connections or listening ports
net useMap network sharesDrive mapping/login script issues
net userManage local usersLocal account reset or review
gpupdateRefresh Group PolicyPolicy change not applied yet
gpresult /rShow applied policiesConfirm user/computer policy scope
chkdskCheck file system/disk errorsFile corruption or improper shutdown
sfc /scannowVerify/repair protected system filesMissing/corrupt Windows files
DISM /Online /Cleanup-Image /RestoreHealthRepair Windows component storeUse when SFC cannot repair everything
diskpartAdvanced disk/partition managementPowerful; wrong disk selection is destructive
robocopyRobust file copyPreserve directory structures and retry copies
tasklistList running processesCommand-line process review
taskkillEnd a processHung application or script
shutdownRestart/shut down from CLIRemote or scripted shutdown scenarios
bootrecBoot repair in recovery environmentMBR/BCD repair scenarios
bcdbootRebuild boot filesUEFI/GPT boot repair scenarios
Notes and examples

Linux and macOS Commands

CommandPrimary useNotes
lsList filesUse options for details/hidden files
cdChange directoryKnow absolute vs relative paths
pwdPrint working directoryConfirms current path
cpCopy filesRecursive copy needed for directories
mvMove/renameCan overwrite if careless
rmRemove filesRecursive/force options are dangerous
mkdirCreate directoriesCommon scripting command
catDisplay file contentsGood for short text files
lessView longer text filesSafer than editing
grepSearch textCommon log and config search tool
findLocate filesSearches by name, type, time, size
chmodChange permissionsNumeric modes such as 755 are common
chownChange ownershipRequires elevated privileges
psShow processesPair with grep for process search
killSend signal to processUse process ID
sudoRun command with elevated privilegesPrefer over logging in directly as root
suSwitch userOften used to become root where allowed
dfFile system free spaceUse for full disk symptoms
duDirectory space usageFind large folders
ifconfig or ipNetwork interface infoip is common on modern Linux
pingConnectivity testSame concept as Windows
traceroutePath traceEquivalent concept to tracert
dig or nslookupDNS testingdig is common on Linux/macOS
manManual pagesBuilt-in command reference
apt, dnf, yumPackage managementDistribution-specific
passwdChange passwordLocal account password command

Command-line quick review

Memorize what each command is for, not just its name.

CommandUseExam trap
ipconfigView IP configuration; release/renew DHCP; flush DNS cacheDNS cache flush does not fix a bad gateway
pingBasic connectivity and name-resolution checkICMP may be blocked; failure is not always outage
tracertPath to destination and where routing may failIt does not prove application-layer availability
nslookupDNS query testingIf DNS works, the app can still fail for other reasons
netstatActive connections and listening portsRequires interpretation; many connections may be normal
net userView/create/manage local users from CLILocal account commands do not manage cloud/domain identities
net useMap network drives/resourcesDrive mapping failure may be permissions or DNS
gpupdateRefresh Group PolicyPolicy may not apply if scope/filtering is wrong
gpresultShow applied policiesBetter for policy troubleshooting than guessing
chkdskFile system/disk checksNot a backup; can take time and may require reboot
sfcVerify/repair protected Windows system filesNot designed to fix third-party applications
DISMRepair Windows image/component storeOften used before or with SFC in corruption scenarios
shutdownShutdown/restart/logoff from CLIUseful for remote or scripted administration
robocopyRobust file copy/syncWrong switches can mirror deletion; test carefully
xcopyLegacy extended copyKnow it, but robocopy is often stronger
diskpartDisk/partition managementDangerous if wrong disk is selected
formatPrepare a volume with a file systemDestroys existing data on target volume

Linux and macOS command awareness

Command/toolPlatformHigh-yield use
ls, cd, pwdLinux/macOSNavigate and list files
cat, less, tailLinux/macOSView files/logs
grepLinux/macOSSearch text/output
chmodLinux/macOSChange permissions
chownLinux/macOSChange ownership
ps, topLinux/macOSView processes/resource usage
killLinux/macOSStop a process
sudoLinux/macOSRun command with elevated privileges
ifconfig / ipLinux/macOS/LinuxNetwork configuration review
manLinux/macOSCommand documentation
apt, dnf, yumLinuxPackage management, depending on distribution
Disk UtilitymacOSDisk formatting/repair
Activity MonitormacOSProcess and performance review
Keychain AccessmacOSCredentials/certificates
Time MachinemacOSBackup and restore

Security Cheat Sheet

Security Principles

ConceptMeaningExam decision point
CIA triadConfidentiality, integrity, availabilityIdentify which goal a control protects
Least privilegeGive only required accessPrefer standard user over administrator
Defense in depthMultiple layered controlsNo single control is enough
Zero trustVerify explicitly; assume no implicit trustStrong identity, device posture, and least privilege
AAAAuthentication, authorization, accountingLogin, permissions, and logging are separate
Non-repudiationProof that an action occurredLogs, signatures, and audit trails
Separation of dutiesSplit sensitive tasksReduces fraud and mistakes
Need to knowAccess only to required dataOften paired with least privilege
Notes and examples

Authentication and Account Controls

ControlUse forTrap
PasswordBasic knowledge factorComplexity alone does not stop reuse or phishing
PINDevice-bound quick sign-inNot the same as a reusable password
BiometricsInherence factorUsually paired with device security
Smart card/security keyPossession factorStronger than password-only login
MFAUses two or more factor typesTwo passwords are not true MFA
SSOOne identity for many appsConvenient but high-impact if compromised
Password managerUnique complex passwordsProtect the vault with MFA
Account lockoutSlows brute force attacksCan cause denial-of-service if too aggressive
UACPrompts for elevationDoes not replace NTFS permissions
Local accountStored on one deviceNot centrally managed
Domain accountManaged by directory serviceCentral policy and access control
Cloud identityUsed for SaaS/cloud servicesCheck sync, MFA, and conditional access symptoms

Permission and Sharing Rules

ItemWhat to remember
NTFS permissionsApply locally and over network; support inheritance
Share permissionsApply only over network share access
Effective permissionsCombination of user, group, inherited, explicit, share, and NTFS controls
Most restrictive resultWhen share and NTFS both apply, the more restrictive effective access wins
Explicit DenyUsually overrides Allow; use sparingly
InheritanceChild objects inherit parent permissions unless inheritance is changed
OwnershipOwner can usually change permissions; taking ownership is a major admin action
Move vs copyPermissions may be retained or inherited depending on volume and operation
GroupsAssign permissions to groups, not individual users, when possible

Wireless and Network Security Choices

NeedChooseAvoid
Secure Wi-FiWPA2/WPA3 with strong passphrase or enterprise authWEP, weak PSK, shared passwords
Guest accessGuest network/VLAN isolationPutting guests on internal LAN
Easier device onboardingQR code or managed provisioningWPS if security is a concern
Remote administrationVPN or secure management pathOpen RDP/SSH to the internet
Secure web accessHTTPSHTTP for sensitive logins
Secure shell accessSSHTelnet
Secure file transferSFTP/FTPS/HTTPSPlain FTP
Internal name resolution issueDNS troubleshootingAssuming internet outage first
Suspected rogue wirelessCheck SSIDs, BSSIDs, placement, logsTrusting SSID name alone

Common Ports and Secure Alternatives

ServiceCommon portSecurity note
SSH22Secure remote CLI
DNS53Required for name resolution; can be abused
HTTP80Not encrypted
HTTPS443Encrypted web traffic
SMB445Windows file sharing; restrict exposure
RDP3389Protect with VPN/MFA/strong policy
SMTP25, 587Mail sending; 587 commonly used for authenticated submission
POP3110, 995995 is encrypted POP3
IMAP143, 993993 is encrypted IMAP
LDAP389, 636636 is LDAPS
Kerberos88Common domain authentication protocol

Authentication and account security

ControlWhat it protects againstReview point
MFAPassword-only compromiseStronger when factors are truly different
Password managerWeak/reused passwordsProtect the vault with strong MFA
Account lockoutBrute-force attemptsToo strict can cause denial-of-service issues
BiometricsCredential sharing and convenience issuesUsually paired with device or PIN
Smart card/security keyPhishing-resistant authentication in some setupsRequires enrollment and recovery process
Single sign-onReduces password promptsA compromised primary identity has broad impact
Local admin restrictionMalware and accidental system changesUse standard accounts for daily work
Screen lockUnauthorized local accessShort timeout for shared/public areas

Endpoint hardening

ControlWhy it matters
Patch OS and applicationsReduces known vulnerabilities
Enable host firewallLimits unsolicited inbound access
Use antivirus/EDR protectionsDetects and blocks malware behavior
Disable unused servicesReduces attack surface
Remove unnecessary appsFewer vulnerabilities and conflicts
Encrypt storageProtects data if device is lost or stolen
Use secure boot/firmware protectionsHelps protect startup integrity
Configure automatic lockReduces walk-up access risk
Use standard user accountsLimits damage from user mistakes and malware

Wireless and network security

TopicHigh-yield point
WPA2/WPA3Prefer modern encryption over obsolete wireless security
WPSConvenient but often discouraged in secure setups
Guest networkIsolates visitors from internal resources
Strong passphrasePrevents easy unauthorized access
MAC filteringWeak as a primary security control
SSID hidingNot real security by itself
Captive portalCommon in public/guest environments
VPNProtects traffic over untrusted networks and supports remote access
DNS filteringHelps block known malicious domains
Firewall profilesPublic networks should be more restrictive than private/domain profiles

Social engineering recognition

AttackRecognition cue
PhishingDeceptive message asking for credentials/action
Spear phishingTargeted phishing using personal or business context
WhalingTargets executives or high-value users
VishingVoice-based social engineering
SmishingSMS/text phishing
ImpersonationPretending to be support, vendor, executive, courier
Shoulder surfingObserving screens/keystrokes
TailgatingFollowing an authorized person into a restricted area
Dumpster divingSearching discarded materials
Evil twinRogue wireless network posing as legitimate
On-path attackIntercepting/modifying communications between parties

Data handling and disposal

ScenarioBest practice
Sensitive file no longer neededSecure deletion according to policy
Disk repurposed internallyWipe or reimage according to data classification
Disk leaving organizationSanitize, destroy, or follow approved chain-of-custody process
Lost encrypted laptopVerify encryption status and report through incident process
Shared printer outputRetrieve promptly; use secure print where appropriate
Emailing sensitive dataUse approved encryption and recipients only
Ticket notesDo not expose unnecessary secrets or personal data

Malware, Social Engineering, and Hardening

Malware and Attack Types

ThreatKey clueResponse focus
VirusAttaches to files/programsScan, remove, restore clean files
WormSelf-propagates over networkIsolate and patch vulnerable systems
TrojanDisguised as legitimate softwareRemove payload and source app
RansomwareEncrypts files and demands paymentIsolate, preserve evidence, restore from clean backup
SpywareTracks activityRemove, review browser/app permissions
KeyloggerCaptures keystrokesRemove and reset credentials from clean device
RootkitHides deeply in OSOffline scan or rebuild may be required
CryptominerHigh CPU/GPU use, unknown processRemove malware and patch entry point
PhishingFraudulent message/linkVerify sender and report
Spear phishingTargeted phishingHigher credibility; verify out of band
SmishingSMS phishingDo not use message links
VishingVoice phishingVerify caller identity independently
Shoulder surfingObserving screen/keyboardPrivacy filters and awareness
TailgatingFollowing into secure areaBadge enforcement
Dumpster divingSearching discarded dataShred and sanitize
Evil twinFake Wi-Fi APVerify network identity, use VPN where appropriate
Rogue APUnauthorized AP on networkLocate, disconnect, investigate
Notes and examples

Malware Removal Workflow

StepActionExam note
1Identify and research symptomsPop-ups, redirects, slow system, unknown processes, disabled security
2Quarantine infected systemDisconnect network to prevent spread or data loss
3Disable restore points if usedPrevent restoring infected state; re-enable after cleanup
4RemediateUpdate anti-malware, scan, remove, or rebuild if needed
5Schedule scans and run updatesPatch OS, apps, browsers, plugins
6Re-enable restore and create clean pointOnly after system is verified clean
7Educate userExplain cause, prevention, and reporting path
8DocumentRecord symptoms, actions, tools, and outcome

Endpoint Hardening Checklist

  • Use standard user accounts for daily work.
  • Apply OS, browser, firmware, and application updates.
  • Enable host firewall and endpoint protection.
  • Remove unnecessary software, services, browser extensions, and startup items.
  • Use full-disk encryption on portable devices.
  • Enforce screen lock and strong authentication.
  • Disable autorun/autoplay where appropriate.
  • Restrict local administrator membership.
  • Back up important data and test restores.
  • Log security events and review alerts.

Software Troubleshooting Reference

CompTIA Troubleshooting Method

StepActionWhat not to skip
1Identify the problemQuestion user, identify changes, back up data if needed
2Establish a theory of probable causeStart with simple/common causes
3Test the theoryIf theory fails, establish a new one or escalate
4Establish and implement a plan of actionConsider business impact
5Verify full functionality and implement preventive measuresConfirm with the user when appropriate
6Document findings, actions, and outcomesRequired for repeatability and support history
Notes and examples

Windows Software Symptoms

SymptomLikely checksPossible fix
Slow performanceTask Manager, startup apps, disk space, malware, updatesDisable unnecessary startup items, remove malware, free space, upgrade resources
App crashesEvent Viewer, app updates, compatibility, permissionsRepair/reinstall app, update dependencies, run compatibility mode
Missing DLL or dependencyApp install state, runtime packagesRepair app or reinstall required runtime
Blue screen/restart loopDrivers, hardware changes, updates, Event ViewerSafe Mode, roll back driver, uninstall update, system restore
Service will not startServices console, dependencies, account permissionsCorrect startup type, credentials, dependency service
Windows update failureDisk space, services, network, logsFree space, restart update services, run troubleshooter, repair components
User cannot access fileNTFS/share permissions, ownership, encryptionCorrect group membership or permissions
Profile issueLocal profile corruption, sync errorsRecreate profile after data backup
Certificate warningDate/time, hostname mismatch, untrusted certCorrect clock, verify site, install trusted certificate only when appropriate
Browser redirects/pop-upsExtensions, proxy settings, malwareRemove extensions, reset browser, scan system
Cannot install softwareAdmin rights, OS compatibility, installer integrityUse admin approval, correct version, trusted source
App blockedSecurity policy, SmartScreen, allowlistVerify trust, then adjust policy if authorized
File association wrongDefault apps, registry/app installReset default app association
Drive fullDisk Cleanup, temp files, large profilesRemove temp files, archive data, expand storage
No network after updateDriver, IP settings, VPN, firewallRoll back driver, renew IP, check firewall/VPN

Boot and Recovery Decision Table

ProblemFirst optionsEscalation
Windows fails after driver updateSafe Mode, roll back driverSystem Restore or uninstall update
Boot files damagedStartup Repairbootrec, bcdboot, or rebuild
Corrupt system filesSFCDISM, then rerun SFC
OS unstable after recent changeSystem RestoreReset/reinstall if unresolved
User data at riskBoot to recovery media and back upRemove drive or use external tools if authorized
macOS disk issueRecovery, Disk Utility First AidRestore from Time Machine or reinstall macOS
Linux boot/config issueRecovery/single-user mode, logsRepair bootloader or restore config backup

Browser and SaaS Troubleshooting

SymptomCheck
Works in one browser, not anotherCache, cookies, extensions, browser version
Login loopCookies blocked, SSO issue, time skew, MFA challenge
Access deniedAccount status, license/entitlement, group membership, conditional access
Slow web appBrowser cache, network latency, DNS, service status
Certificate errorSystem time, hostname, trust chain, inspection proxy
Pop-ups/toolbarsExtensions, notifications, malware
Sync not workingAccount sign-in, storage quota, network, service health
MFA prompt repeatedly failsClock sync, registered device, push fatigue, phone change

Core troubleshooting method

Use the standard troubleshooting flow whenever the question asks for the “next” or “best” action.

StepWhat it meansCandidate trap
Identify the problemGather symptoms, question the user, determine changes, duplicate issue if possibleFixing before understanding scope
Establish a theoryStart with probable cause; consider simple causes firstChoosing rare causes without evidence
Test the theoryConfirm or rule out the causeMaking irreversible changes as a “test”
Establish a planDecide remediation and consider effectsNo rollback plan or user impact check
Implement solutionApply the fix or escalateEscalating too late or too early
Verify functionalityConfirm the issue is resolved and preventive steps workStopping after the first successful reboot
Document findingsRecord cause, action, outcome, and future preventionTreating documentation as optional

Scope decision rules

If the issue affects…Think first about…
One user on one deviceProfile, local settings, permissions, app config, cached credentials
One device for all usersOS corruption, local service, driver, hardware, firewall, disk, malware
Many users on one applicationApplication service, update, certificate, authentication, server-side change
Many users on the networkDNS, DHCP, routing, firewall, identity provider, shared service outage
Only remote usersVPN, MFA, conditional access, endpoint compliance, split tunnel, DNS
Only after an updateDriver rollback, update history, compatibility, known issue, restore point

Windows symptom table

SymptomLikely areas to checkBetter first action than reinstalling
App crashes on launchUpdates, dependencies, permissions, profile corruption, event logsCheck Event Viewer/Reliability Monitor
App works for admin onlyFile/registry permissions, elevation requirementAdjust permissions or app configuration
Slow systemStartup apps, disk health, memory pressure, malware, updatesUse Task Manager/Resource Monitor
BSODDriver, hardware, memory, update, firmwareCheck stop information, recent changes, drivers
Windows update failsDisk space, services, network/proxy, corrupted update cacheReview update history and logs; retry after clearing issue
Printer unavailableSpooler, driver, queue, network path, default printerCheck queue/spooler/connectivity
No soundOutput device, mute, driver, service, app settingVerify selected output and driver
Cannot access shareDNS, credentials, permissions, offline server, firewallTest path, credentials, effective permissions
Time/date wrongTime service, time zone, CMOS/firmware, domain syncCorrect sync source and time zone
Certificate warningWrong date/time, expired cert, interception, wrong hostnameDo not bypass without validation

Browser troubleshooting

SymptomPossible cause
Pop-ups/redirectsMalicious extension, adware, notification permission, DNS issue
Certificate errorsDate/time wrong, expired certificate, captive portal, inspection proxy
One site failsDNS cache, browser cache, site issue, security block
All sites failNetwork, proxy, DNS, firewall, VPN
Slow browser onlyExtensions, cache, profile, hardware acceleration
Saved passwords missingProfile sync issue, browser profile, password manager problem

Quick checks: private/incognito window, alternate browser, disable extensions, clear cache for the affected site, verify proxy/VPN, check DNS, review security warnings.

Mobile OS and app troubleshooting

SymptomReview actions
App crashesUpdate app/OS, clear cache where supported, reinstall app, check permissions
Battery drains quicklyReview battery usage, background activity, radios, location, failing battery
Device overheatsHeavy app, charging issue, environment, battery problem
Cannot email/syncCredentials, MFA, server settings, network, account lock, storage
Location not workingPermissions, location services, airplane mode, app settings
No networkAirplane mode, Wi-Fi/cellular settings, SIM/eSIM, carrier issue, VPN
Storage fullRemove unused apps/media, clear cache, cloud sync settings
Suspicious behaviorRemove unknown apps/profiles, scan where supported, update OS, reset if needed

Trap: assuming every mobile issue is hardware. App permissions, account authentication, and OS updates are frequent causes.

Mobile OS and Application Security

Need or symptomCheck or choose
Lost or stolen phoneRemote lock/wipe, account password reset, revoke sessions
BYOD managementMDM/MAM policy, containerization, minimum OS version
Excessive permissionsReview app permissions and privacy settings
Battery drainBackground apps, location services, push sync, malware
App crashesUpdate app/OS, clear cache, reinstall app
No email syncCredentials, MFA/app password policy, server settings, network
Untrusted app sourceAvoid sideloading unless explicitly authorized
Public Wi-Fi useVPN, HTTPS, avoid sensitive work if untrusted
Device resale/disposalBack up, sign out, factory reset, remove from account/MDM
Screen lockPIN/passcode/biometric with auto-lock

Backup, Recovery, and Data Handling

Backup Types

TypeCapturesRestore characteristic
FullAll selected dataSimplest restore; more storage/time
IncrementalChanges since last backup of any typeEfficient backup; restore needs chain
DifferentialChanges since last full backupLarger over time; restore needs full plus latest differential
ImageEntire system/volume stateUseful for bare-metal recovery
File-levelSelected files/foldersGood for user data
SnapshotPoint-in-time stateFast rollback; not always a separate backup
Cloud backupOffsite copyDepends on bandwidth, account, provider availability
Offline backupDisconnected copyHelps against ransomware
Notes and examples

Recovery Terms

TermMeaningExam use
RPOMaximum acceptable data lossDetermines backup frequency
RTOMaximum acceptable downtimeDetermines recovery method and urgency
VersioningMultiple historical copiesHelps recover from accidental overwrite
RetentionHow long backups are keptBalance recovery needs and storage policy
Test restoreProves backup is usableBackup is not complete until restore is verified
3-2-1 strategyMultiple copies, media types, and offsite copyBest-practice concept, not a substitute for policy

Data Destruction and Disposal

Media/dataAppropriate actionNotes
Paper recordsShred or use approved destruction binProtects printed sensitive data
Hard drivesWipe, degauss where appropriate, or destroyDegaussing does not apply to all media types
SSDs/flashSecure erase or physical destructionWear leveling makes simple overwrite less reliable
Optical mediaShred/crushDo not just throw away
Mobile devicesFactory reset, remove accounts, wipe via MDMVerify encryption and account removal
Toner/printer partsRecycle per policyAvoid spills and environmental mishandling
BatteriesRecycle properlyDo not puncture or discard casually

Operational Procedures

Change Management

PhaseTechnician responsibility
RequestDefine what is changing and why
Impact analysisIdentify affected users, systems, risks, and rollback needs
ApprovalGet authorization before production changes
CommunicationNotify stakeholders of timing and impact
ImplementationFollow documented steps
RollbackRestore previous state if change fails
ValidationTest system and user functionality
DocumentationRecord final state, issues, and lessons learned
Notes and examples

Documentation and Ticketing

RecordInclude
TicketUser, asset, symptoms, priority, contact method
Troubleshooting notesTests, results, error messages, timestamps
Change recordScope, approval, schedule, rollback plan
Asset recordSerial/tag, owner, location, warranty/support status
Knowledge base articleSymptoms, cause, resolution, prevention
Incident recordTimeline, affected data/systems, containment, escalation

Safety and Environmental Practices

SituationCorrect response
Working inside PCPower off, unplug when appropriate, use ESD protection
ESD-sensitive componentsUse antistatic strap/mat, handle by edges
Heavy equipmentUse proper lifting or get assistance
Liquid spillDisconnect power safely, follow site procedure
Battery swellingStop use, isolate safely, follow disposal process
Laser printer serviceBe careful around fuser heat and toner
Chemical exposureRefer to safety data sheet and PPE guidance
FireUse correct extinguisher type and evacuate if unsafe
Cable hazardsRoute and secure cables to prevent trips
E-wasteRecycle through approved process

Professional Communication

ScenarioBest practice
Upset userListen, acknowledge, avoid blame
Nontechnical userUse plain language, avoid jargon
Need downtimeExplain impact and expected duration
Unauthorized requestFollow policy; do not bypass controls
Privacy-sensitive data visibleMinimize exposure and do not discuss unnecessarily
Escalation neededProvide concise summary and evidence
Work completedVerify with user and document outcome
Mistake madeReport promptly and follow remediation process

Change management

StepWhy it matters
Define the changePrevents unclear or expanding work
Identify risk and impactAvoids surprise outages
Get approvalEnsures accountability
Schedule maintenance windowReduces user disruption
CommunicateSets expectations
Back up and create rollback planAllows recovery if change fails
Implement and testConfirms intended result
Document outcomeSupports future troubleshooting

Trap: making an urgent fix without documenting what changed. In later troubleshooting questions, the undocumented change is often the hidden cause.

Ticketing and documentation

Good ticket notes usually include:

  • User/device/application affected
  • Symptoms and error messages
  • Time started and recent changes
  • Scope and business impact
  • Troubleshooting steps already tried
  • Root cause if known
  • Fix applied
  • Verification performed
  • User communication and follow-up
  • Escalation details if applicable

Avoid recording passwords, unnecessary personal data, or unapproved sensitive details in tickets.

Professional communication

SituationStrong technician behavior
User is frustratedListen, acknowledge, ask focused questions
User caused the issueAvoid blame; educate respectfully
You need more timeSet expectations and provide updates
Issue is outside your authorityEscalate with clear notes
You do not know the answerSay you will research or escalate; do not guess
Working around sensitive dataMaintain privacy and follow policy
Remote support sessionGet permission before taking control or viewing files

Safety and environmental procedures

TopicReview point
ESDUse antistatic handling, grounding, proper bags/mats
Electrical safetyDisconnect power where appropriate; avoid unsafe equipment
BatteriesHandle swollen/damaged batteries carefully; follow disposal rules
LiftingUse proper lifting technique and assistance for heavy equipment
CablesAvoid trip hazards and blocked airflow
Toner/chemicalsFollow safety documentation and disposal practices
Fire suppressionUse the correct class/type for the environment
VentilationPrevent overheating and exposure to fumes
Personal protective equipmentMatch PPE to task and workplace policy

Scripting and Automation Basics

ConceptKnow
Script typesBatch, PowerShell, Bash, Python, JavaScript
VariableStores reusable value
ConditionalRuns logic based on true/false test
LoopRepeats actions
FunctionReusable block of code
CommentExplains code; ignored by interpreter
Input validationPrevents bad or unsafe input
Error handlingResponds to failures predictably
Exit codeIndicates success/failure to calling process
SchedulingUse Task Scheduler, cron, or management platform
SecurityDo not run unknown scripts; review source and permissions
Least privilegeRun automation with only required rights
TestingTest in nonproduction or limited scope first
Notes and examples

Script Decision Points

TaskGood script candidate?Why
Rename many filesYesRepetitive and rule-based
Collect logs from many devicesYesConsistent output and time savings
One-time uncertain repairMaybeManual verification may be safer
Delete files across profilesHigh riskRequires backup, testing, and narrow scope
Change security settingsHigh riskRequires approval and rollback plan
Install approved app on many PCsYesUse management tools and logging

Scripting and automation basics

The CompTIA A+ Core 2 (220-1202) candidate does not need to be a software engineer, but should understand what scripts do and why they can be risky.

ConceptReview point
VariablesStore values such as paths, usernames, or counters
Environment variablesSystem/user values like paths and temp locations
ConditionalsRun different actions based on true/false tests
LoopsRepeat actions; dangerous if logic is wrong
CommentsExplain script purpose and assumptions
Exit codesIndicate success/failure for automation
Input validationPrevents bad data from causing damage
PermissionsScripts run with the privileges of the executing context
TestingRun in a safe environment before production
Signing/execution policyHelps control unauthorized scripts

File extensions to recognize

ExtensionTypical association
.bat / .cmdWindows batch scripts
.ps1PowerShell
.shShell script
.pyPython
.jsJavaScript
.vbsVBScript

Script trap: a script that deletes, moves, formats, changes permissions, or modifies many accounts should be treated as high risk. Review it, test it, back up first, and confirm the target path or scope.

High-Yield Traps to Review

TrapCorrect distinction
Encryption equals backupEncryption protects confidentiality; backup protects recovery
RAID equals backupRAID improves availability; it does not replace backups
Admin account for daily workUse standard user; elevate only when needed
Share permission onlyNTFS permissions also apply to network access
Explicit Deny everywhereDeny can override Allow and cause difficult troubleshooting
SSID hiding is strong securityIt is not a substitute for WPA2/WPA3 and strong authentication
MAC filtering is strong securityMAC addresses can be spoofed
Antivirus alone stops all malwareLayer controls: patching, least privilege, filtering, backups, training
Reinstall firstPreserve data and diagnose before destructive action
Clear logs to fix issueLogs are evidence; preserve relevant records
SFC and DISM are identicalSFC checks protected system files; DISM repairs component store
UAC is permission managementUAC controls elevation prompts; permissions still matter
Public vs private firewall profilePublic is more restrictive; wrong profile can block services
Local policy vs domain policyDomain policy can override local settings
System Restore is user backupIt rolls back system state, not a full user data backup
Safe Mode fixes issue permanentlyIt isolates causes; still remediate root cause
Notes and examples

“Best next step” traps

  • Choosing a final fix before confirming the problem.
  • Reimaging before checking logs, drivers, updates, or user profile issues.
  • Escalating without collecting basic information.
  • Continuing troubleshooting after discovering a security incident that must be isolated/escalated.
  • Making a change without rollback or documentation.
  • Bypassing certificate or security warnings for convenience.
  • Giving admin rights instead of fixing the specific permission problem.
  • Assuming wireless signal strength means authentication, DHCP, DNS, and internet access all work.
  • Confusing backup, sync, restore point, and full system image.
  • Treating user education as optional after malware or phishing events.

Tool-selection traps

If asked to…Prefer…Not usually…
Find why an app crashed yesterdayReliability Monitor/Event ViewerRandomly reinstalling drivers
See current CPU/memory hogsTask Manager/Resource MonitorRegistry Editor
Troubleshoot policy applicationgpresult, gpupdate, policy toolsChanging local settings blindly
Check DNS resolutionnslookup, ipconfig /displaydnsReplacing the NIC
Repair Windows system filessfc, DISMFormatting the disk first
Manage partitionsDisk Management/diskpartFile Explorer permissions
Investigate malware symptomsSecurity tools, isolation, logsIgnoring network spread risk

Last-Week Review Checklist

  • Match Windows tools to symptoms without guessing.
  • Practice command purposes, especially network, boot, disk, and system repair commands.
  • Review NTFS/share permission interactions and Deny behavior.
  • Memorize malware removal order and why quarantine comes early.
  • Compare backup types and recovery use cases.
  • Review Wi-Fi, browser, MFA, account, and SaaS access troubleshooting.
  • Practice deciding when to repair, restore, reset, reimage, or escalate.
  • Review change management, documentation, safety, and user communication scenarios.
  • For performance-based questions, read the task carefully before changing settings.

High-yield Core 2 map

AreaWhat to review quicklyWhat questions often test
Operating systemsWindows features, installation methods, recovery tools, file systems, command-line utilities, macOS/Linux basicsBest tool for a task, correct installation/recovery choice, command output interpretation
SecurityAuthentication, permissions, malware response, endpoint hardening, wireless security, social engineering, data handlingLeast privilege, order of response, secure configuration, recognizing attack types
Software troubleshootingBoot issues, OS errors, application crashes, update failures, browser symptoms, mobile OS issuesMost likely cause, next troubleshooting step, safe remediation
Operational proceduresDocumentation, change management, safety, professionalism, backups, scripting risks, environmental controlsTechnician behavior, escalation, rollback planning, evidence preservation

Exam-day thinking pattern

When a question gives a scenario, slow down and identify what it is really asking:

  1. Symptom — What is broken or risky?
  2. Scope — One user, one device, many users, one application, entire network?
  3. Recent change — Update, driver, policy, installation, permission change, malware event?
  4. Impact — Data loss risk, security incident, safety issue, business outage?
  5. Best next step — Verify, contain, document, escalate, remediate, or test?

A common mistake is jumping to a dramatic fix—reimage, replace hardware, reinstall OS—before checking simpler or safer causes such as credentials, permissions, network settings, services, updates, or user profile issues.

Windows administration toolbox

Know the right tool for the task. Many exam questions are essentially tool-selection questions.

ToolBest useCommon trap
Task ManagerProcesses, performance, startup apps, quick service viewUsing it for deep historical logs
Event ViewerSystem/application/security logs and error patternsIgnoring timestamps and event source
Device ManagerDrivers, disabled devices, hardware conflictsReinstalling OS for a driver issue
Disk ManagementPartitions, volumes, drive lettersConfusing it with file-level permissions
ServicesStart/stop/configure servicesDisabling services without dependency review
System ConfigurationStartup and boot troubleshootingPermanent changes without documenting
Performance MonitorCounters and long-term performance analysisUsing it when Task Manager is enough
Resource MonitorReal-time CPU, disk, network, memory detailOverlooking disk queue or network activity
Reliability MonitorTimeline of crashes, updates, and failuresForgetting it is useful after “it started yesterday”
Registry EditorLow-level OS/application configurationEditing without backup or exact instruction
Local Users and GroupsLocal account/group managementNot available in all environments/editions
Local Security PolicyLocal password/audit/security settingsConfusing local policy with domain policy
Group Policy toolsManaged policy application and troubleshootingAssuming local settings override domain policy
Windows Defender FirewallHost firewall rules and profilesOpening broad inbound access unnecessarily
Windows Security toolsAntivirus, threat protection, device securityDisabling protection instead of adding controlled exclusions
Windows UpdatePatch status and update historyIgnoring rollback/uninstall options
Backup and recovery toolsRestore files/system stateBackups are useful only if restore works

Permissions and access control

Core permission principles

PrincipleMeaningExam application
Least privilegeGive only the access requiredAvoid making users local admins for convenience
Need to knowAccess should match job role and data sensitivityRestrict confidential files by group/role
Separation of dutiesSplit sensitive tasks across rolesOne person should not control all critical steps
Role-based accessAssign rights through groups/rolesManage groups, not one-off user exceptions
Explicit denyDeny can override allow in many permission modelsUse carefully; it can block intended access
InheritancePermissions flow from parent containersCheck inherited permissions before adding new ones
Notes and examples

NTFS and share permission traps

SituationRule of thumb
Local access to filesNTFS permissions apply
Network access to shared folderBoth share and NTFS permissions matter
Share allows Full Control, NTFS allows ReadEffective network access is limited by NTFS
Share allows Read, NTFS allows ModifyEffective network access is limited by share permission
User belongs to multiple groupsCombined allows generally accumulate, but denies can override
User suddenly loses accessCheck group membership, inheritance, explicit deny, moved folder, token refresh/sign-out

Candidate mistake: selecting “reinstall the application” when the actual issue is that the user cannot write to a folder, access a share, or inherit the right group membership.

Malware and incident response

Malware types to distinguish

TypeCore behavior
VirusAttaches to files/programs and spreads through execution
WormSelf-propagates across systems/networks
TrojanDisguises itself as legitimate software
RansomwareEncrypts or blocks access and demands payment
SpywareCollects information without consent
KeyloggerCaptures keystrokes
RootkitHides privileged malicious activity
Botnet agentEnrolls device into remote-controlled network
CryptominerUses system resources to mine cryptocurrency
Adware/PUPDisplays ads or unwanted behavior; may be bundled
Notes and examples

Malware response sequence

A practical endpoint malware-removal sequence is:

  1. Identify symptoms — pop-ups, redirects, disabled security tools, high CPU, unknown processes, file encryption, suspicious network traffic.
  2. Isolate or quarantine — disconnect from network if needed to prevent spread or data loss.
  3. Preserve what matters — if it may be an incident, follow policy before wiping evidence.
  4. Disable persistence where applicable — startup entries, scheduled tasks, malicious services, browser extensions.
  5. Update tools and scan — use trusted antimalware and offline scanning if appropriate.
  6. Remediate — remove malware, repair settings, patch exploited software, reset affected credentials.
  7. Verify — rescan, confirm symptoms are gone, check logs and network behavior.
  8. Restore protections — firewall, antivirus, updates, restore/recovery features where applicable.
  9. Educate user and document — record cause, impact, actions, and prevention.

Common trap: immediately deleting or reimaging a system that may require evidence preservation, management approval, or incident escalation.

Security troubleshooting scenarios

ScenarioBest first thinking
User reports suspicious emailDo not click links; report/quarantine according to policy
Workstation shows ransomware noteIsolate immediately; escalate; preserve evidence; follow incident plan
User cannot access encrypted driveRecovery key, TPM/firmware change, account permissions
Browser redirects to unknown search pageExtension/adware/DNS settings; scan and reset browser settings
Repeated account lockoutsMapped drives, saved credentials, mobile email, brute-force attempt
Unknown admin account appearsTreat as security incident; investigate and escalate
Antivirus disabledCheck policy, tampering, malware, service status
Public Wi-Fi useVPN, firewall public profile, avoid sensitive activity without protection

Backups and recovery

Backup types

TypeWhat it doesRestore implication
FullCopies all selected dataSimplest restore, more storage/time
IncrementalCopies changes since last backup of any typeRestore needs last full plus each incremental
DifferentialCopies changes since last full backupRestore needs last full plus latest differential
ImageCaptures system state/disk imageUseful for bare-metal or standardized recovery
File-levelCaptures selected files/foldersGood for user data restore
Cloud backup/syncStores data off-deviceSync is not always the same as versioned backup

Backup decision rules

  • Test restores. A backup is only useful if restoration works.
  • Keep offline or immutable copies where ransomware risk matters.
  • Match recovery method to the problem: deleted file, corrupted profile, failed disk, or compromised system require different recovery choices.
  • Protect backup credentials. Backup systems are high-value targets.
  • Document retention according to organizational policy.

Practice priorities before a mock exam

Use original practice questions to test whether you can apply concepts under exam-style wording. Do not only memorize tables.

Topic drills to run first

Drill areaWhat to prove
Windows toolsChoose the correct utility for a scenario
CommandsMatch command to symptom and interpret basic purpose
PermissionsCalculate effective access and identify least-privilege fix
Malware responsePut containment, remediation, verification, and education in order
Boot troubleshootingSelect Safe Mode, recovery, rollback, repair, or reset appropriately
Browser/mobile issuesIdentify app, permission, network, certificate, or malware causes
Operational proceduresApply documentation, change control, safety, and professionalism
Security hardeningChoose practical endpoint, account, and wireless controls
Notes and examples

How to review explanations

When using a question bank with detailed explanations, review every missed question this way:

  1. Why was the correct answer best?
  2. Which clue in the scenario pointed to it?
  3. Why were the distractors tempting but wrong?
  4. Was the issue scope, sequence, tool choice, or terminology?
  5. What similar scenario could appear with a different symptom?

Final rapid checklist

Before your next CompTIA A+ Core 2 (220-1202) practice exam, confirm you can:

  • Select the correct Windows administrative tool for a troubleshooting task.
  • Distinguish clean install, upgrade, repair, reset, image, and recovery options.
  • Use common Windows commands for network, policy, disk, file, and system repair tasks.
  • Recognize Linux/macOS commands and support tools at a practical level.
  • Apply least privilege, MFA, encryption, firewall, patching, and account-hardening concepts.
  • Troubleshoot NTFS/share permission scenarios.
  • Identify malware types and follow a safe response sequence.
  • Diagnose common application, browser, boot, update, and mobile OS symptoms.
  • Choose safe backup and restore approaches.
  • Apply change management, documentation, safety, privacy, and professional communication.
  • Recognize scripting benefits and risks.

Put the review into practice

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