1.8 Explain common features and tools of the macOS/desktop operating system
📘CompTIA A+ Core 2 (220-1202)
Overview
In macOS, applications can be installed and removed in multiple ways, depending on the file type and source. For the CompTIA A+ exam, you must understand:
- Common macOS application file types
- How applications are installed using:
.dmg.pkg.app- App Store
- How applications are uninstalled properly
- Differences between simple and installer-based apps
- Basic troubleshooting related to application installation and removal
macOS applications are usually stored in the /Applications folder and can run system-wide or for a single user.
macOS Application File Types
macOS uses specific file formats to distribute and install applications. The exam expects you to recognize and understand these file types.
.dmg File (Disk Image)
What is a .dmg file?
- A .dmg (Disk Image) file is a virtual disk container.
- It opens like an external drive when double-clicked.
- It often contains:
- An
.appfile - A shortcut to the Applications folder
- Sometimes a license agreement or instructions
- An
How .dmg Installation Works
- User double-clicks the
.dmgfile - macOS mounts it as a temporary disk
- A window opens showing the app
- User drags the
.appfile into the Applications folder - The disk image is ejected after installation
Key Points for the Exam
.dmgfiles do not install software automatically- They usually require drag-and-drop installation
- No system-wide installer runs
- Very common for third-party macOS apps
.pkg File (Installer Package)
What is a .pkg file?
- A .pkg (Package) file is a full installer package
- It installs software using the macOS Installer
- Often used for:
- System tools
- Drivers
- Enterprise software
- Applications that need system access
How .pkg Installation Works
- User double-clicks the
.pkgfile - macOS Installer launches
- User follows on-screen steps:
- License agreement
- Install location
- Administrator authentication
- Files are installed automatically
Key Points for the Exam
.pkgfiles run an installer- They may install files in:
/Applications/Library/System
- Usually require admin credentials
- More complex than
.dmginstallations
.app File (Application Bundle)
What is a .app file?
- A
.appfile is a macOS application bundle - It looks like a single file but actually contains:
- Program code
- Resources
- Configuration files
- macOS treats it as one object
How .app Files Are Used
- Can be run directly by double-clicking
- Can be moved manually to:
/Applications(recommended)- User’s Applications folder
Key Points for the Exam
.appfiles can be installed by copying them- No installer is required
- Removing the
.appfile usually removes the application
Installing Applications Using the App Store
What is the macOS App Store?
- The App Store is Apple’s official application distribution platform
- Apps are:
- Digitally signed
- Verified by Apple
- Automatically updated
How App Store Installation Works
- User opens the App Store
- Searches for an application
- Clicks Get or Install
- Signs in with Apple ID if required
- App installs automatically into
/Applications
Key Points for the Exam
- App Store apps are sandboxed (limited system access)
- Updates are handled automatically
- Installation is fully automated
- No
.dmgor.pkgfiles are visible to the user
Uninstallation of Applications in macOS
Uninstallation depends on how the app was installed.
Uninstalling Drag-and-Drop Applications (.app or .dmg)
Standard Uninstallation Method
- Open Applications
- Locate the app
- Drag the app to the Trash
- Empty the Trash
Exam Notes
- Works for most
.dmg-installed apps - Removes the main application only
- User data and preference files may remain
Uninstalling App Store Applications
Method
- Open Launchpad
- Click and hold the app icon
- Click the X (if available)
- Confirm deletion
Exam Notes
- Only works for App Store apps
- Automatically removes the app
- Similar to iOS app removal behavior
Uninstalling .pkg-Installed Applications
Why This Is Different
.pkginstallers place files in multiple locations- Deleting the
.appalone may not fully remove the software
Common Methods
- Use the application’s built-in uninstaller (if provided)
- Run a dedicated uninstall
.pkg - Manually remove files from:
/Applications/Library~/Library
Exam Notes
- Not all
.pkgapps can be removed by dragging to Trash - Leftover files can affect system performance or future installs
Common Locations for Application Files (Exam Relevant)
/Applications– Main applications~/Applications– User-specific apps/Library– System-wide support files~/Library– User preferences and caches
Understanding these locations helps with manual troubleshooting.
Security and Permissions Considerations
- Some installations require administrator access
- macOS uses Gatekeeper to block untrusted apps
- Apps may be blocked if:
- Not signed
- From unidentified developers
For the exam, remember:
- Gatekeeper protects macOS from unsafe software
- Users can allow blocked apps through Security & Privacy settings
Key Exam Takeaways (Must Remember)
.dmg= disk image, usually drag-and-drop install.pkg= installer package, uses macOS Installer.app= application bundle- App Store apps install and uninstall automatically
- Dragging an app to Trash works for most simple apps
.pkgapps may require special uninstallers- Application files can exist outside the Applications folder
Summary
macOS application installation is generally simpler than other operating systems, but the method depends on the file type. For the CompTIA A+ exam, you must recognize:
- Installation differences between
.dmg,.pkg,.app, and App Store apps - Proper uninstallation methods
- When admin permissions are required
- Where applications and support files are stored
Understanding these concepts ensures you can install, remove, and troubleshoot macOS applications confidently, which is exactly what CompTIA A+ expects.
