220-1202 — CompTIA A+ Core 2 Quick Reference

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

This independent Quick Reference 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.

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 Quick Reference

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

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 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

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

Security Quick Reference

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

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

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

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

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

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

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

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

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

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

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

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.

Next Step

Use this Quick Reference to target weak areas, then move into timed 220-1202 practice questions and hands-on labs that require choosing the correct tool, command, security control, or troubleshooting step.

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