Fix com.apple.launchd.peruser Crash Loop on macOS

Symptoms

Users experiencing the com.apple.launchd.peruser crash loop may notice the following:

• Repeated pop-up crash reports for com.apple.launchd.peruser.
• High CPU usage (often 100% on one core) by launchd or related processes.
• System becomes sluggish, unresponsive, or freezes intermittently.
• Applications fail to launch or crash unexpectedly.
• Console logs show repeated entries like com.apple.launchd.peruser: (pid X) exited with code Y followed by immediate restart.
• Login items may not load properly.

Root Causes

The crash loop typically stems from one of the following:

• Corrupted user launchd plist files in ~/Library/LaunchAgents/ or /Library/LaunchAgents/.
• Third-party software conflicts (e.g., antivirus, VPN, or system utility tools) that inject agents into launchd.
• Damaged user account preferences or cache files.
• System-level launchd database corruption in /var/db/com.apple.xpc.launchd/.
• macOS update glitches leaving behind incompatible plist versions.
• Permission errors on user library folders.

Step-by-Step Fix

Step 1: Boot into Safe Mode

1. Shut down your Mac.
2. Turn it on and immediately press and hold the Shift key until the login window appears (release when you see the Apple logo).
3. Log in (you may need to log in multiple times in Safe Mode).
4. Safe Mode disables third-party launch agents and performs a directory check. If the crash stops, a third-party agent is likely the cause.
5. Restart normally to exit Safe Mode.

Step 2: Identify and Remove Problematic Launch Agents

1. Open Terminal (from /Applications/Utilities/).
2. List user launch agents:

   ls ~/Library/LaunchAgents/

3. List system launch agents:

   ls /Library/LaunchAgents/

4. Move suspicious plist files (especially those from recently installed apps) to a temporary folder:

   mkdir ~/Desktop/backup_launchagents && mv ~/Library/LaunchAgents/com.suspect.plist ~/Desktop/backup_launchagents/

5. Repeat for /Library/LaunchAgents/ (requires sudo).
6. Reboot and check if the crash loop persists.

Step 3: Reset User Launchd Database (Advanced)

1. Boot into Recovery Mode: Restart and hold Command+R until the Apple logo appears.
2. Open Terminal from the Utilities menu.
3. Remove the user launchd database (replace username with your short username):

   rm -rf /var/db/com.apple.xpc.launchd/disabled.$(id -u username)

4. Reboot.

Step 4: Repair Disk Permissions and Verify Disk

1. In Recovery Mode, open Disk Utility.
2. Select your startup disk and click First Aid → Run.
3. Wait for completion, then reboot.

Step 5: Reset NVRAM and SMC

• Intel Macs: Shut down, then press Option+Command+P+R for 20 seconds after the chime. For SMC, follow Apple's guide.
• Apple Silicon Macs: Simply restart (NVRAM reset is automatic). SMC reset is not applicable.

Alternative Fixes

• Create a new user account: If the crash only affects one user, create a new admin account via System Settings → Users & Groups. Transfer data if needed.
• Reinstall macOS: Boot into Recovery Mode and reinstall macOS without erasing data (preserves files).
• Use EtreCheck or similar tools to scan for problematic launch daemons and agents.

Prevention

• Regularly update macOS and software to avoid compatibility issues.
• Avoid installing unnecessary third-party launch agents.
• Before installing new software, check reviews for known conflicts with launchd.
• Maintain regular backups (Time Machine) to recover from corruption.
• Periodically review ~/Library/LaunchAgents/ and /Library/LaunchAgents/ for unknown plists.

By following these steps, most users can resolve the com.apple.launchd.peruser crash loop and restore normal system performance. If the issue persists, contact Apple Support or consult Apple Communities for further assistance.