ACMT macOS Troubleshooting 1 — Questions and Answers
Question 1: A customer's Mac gets stuck on the gray loading bar during startup. Which startup mode should the technician try first?
- Target Disk Mode
- Safe Mode (Correct answer)
- Recovery Mode
- Verbose Mode
Correct answer: Safe Mode
Safe Mode (holding Shift at startup) disables third-party extensions and performs a directory check, making it the first troubleshooting step for startup hang issues.
Question 2: Which command in macOS Terminal is used to repair disk permissions on an HFS+ volume in Recovery Mode?
- diskutil repairDisk /
- diskutil repairPermissions /
- fsck -fy /dev/disk0 (Correct answer)
- chmod -R 755 /
Correct answer: fsck -fy /dev/disk0
The command 'fsck -fy /dev/disk0' (with the correct disk identifier) is used in single-user or Recovery Mode to check and repair the file system.
Question 3: What does the 'Prohibitory Symbol' (circle with a slash) at startup indicate on a Mac?
- A hardware memory failure
- macOS cannot find a valid, compatible system folder to boot from (Correct answer)
- The user's account is locked
- SSD has failed completely
Correct answer: macOS cannot find a valid, compatible system folder to boot from
The prohibitory symbol means the Mac found a startup disk but cannot use it, usually because macOS is missing, corrupt, or incompatible with the hardware.
Question 4: How does a technician boot a Mac to macOS Recovery on an Apple Silicon Mac?
- Hold Command + R at startup
- Hold the power button until 'Loading startup options' appears (Correct answer)
- Hold Option + D at startup
- Hold Shift at startup
Correct answer: Hold the power button until 'Loading startup options' appears
On Apple Silicon Macs, holding the power button until 'Loading startup options' appears is the correct way to enter recoveryOS.
Question 5: A customer reports that their Mac keeps crashing with a kernel panic. Where should the technician look for clues about the cause?
- System Information > Software
- Console app > Crash Reports / System Diagnostics (Correct answer)
- Finder > Applications
- Disk Utility > First Aid
Correct answer: Console app > Crash Reports / System Diagnostics
The Console app's Crash Reports and System Diagnostics sections contain kernel panic logs (panic.ips files) that identify the crashing process or driver.
Question 6: Which macOS feature must be disabled before a technician can reinstall macOS on an Apple Silicon Mac that is being sent to Apple depot repair?
- FileVault
- Activation Lock (Correct answer)
- Screen Time
- Gatekeeper
Correct answer: Activation Lock
Activation Lock, tied to the user's Apple ID, must be disabled before sending an Apple Silicon Mac for depot repair to allow Apple to perform system-level operations.
ACMT macOS Troubleshooting 1
A customer's Mac gets stuck on the gray loading bar during startup.
Which startup mode should the technician try first?