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

Symptoms

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

• High CPU usage (often 100% by launchd or peruser processes)
• Applications failing to launch or crashing unexpectedly
• System slow to respond or unresponsive
• Repeated crash reports in Console.app under ~/Library/Logs/DiagnosticReports/
• Kernel panics or forced restarts in severe cases

Root Causes

The crash loop is typically caused by one or more of the following:

• Corrupted user-level plist files in ~/Library/LaunchAgents/ or /Library/LaunchAgents/
• Misconfigured third-party launch agents (e.g., from Adobe, Dropbox, or antivirus software)
• System file corruption due to incomplete updates or disk errors
• User account corruption from permissions issues or improper logout
• Outdated macOS version with known launchd bugs

Step-by-Step Fix

Step 1: Identify the Culprit with Console

1. Open Console.app from /Applications/Utilities/
2. In the search bar, type com.apple.launchd.peruser
3. Look for repeated error messages like Exited with code: 1 or Service exited with abnormal code: 78
4. Note the process name (e.g., com.example.service) that appears in the crash logs

Step 2: Disable or Remove Problematic Launch Agents

1. Open Terminal
2. Navigate to the user LaunchAgents folder: cd ~/Library/LaunchAgents
3. List all plist files: ls -la
4. For the identified process, move its plist file to a backup location:

   mv com.example.service.plist ~/Desktop/

5. If the process is system-wide, check /Library/LaunchAgents/ and /Library/LaunchDaemons/ (requires sudo)
6. Restart your Mac or reload launchd:

   sudo launchctl unload -w /Library/LaunchAgents/com.example.service.plist

Step 3: Repair Disk Permissions (macOS High Sierra and earlier)

Note: For macOS Mojave and later, use First Aid in Disk Utility.

1. Boot into Recovery Mode (restart and hold Cmd+R)
2. Open Disk Utility from the Utilities menu
3. Select your startup disk and click First Aid
4. Run First Aid and repair any errors
5. Restart normally

Step 4: Create a New User Account

If the issue persists, create a new administrator account to test if the problem is user-specific:

1. Go to System Settings > Users & Groups
2. Click Add Account and create a new admin user
3. Log out of your current account and log in to the new one
4. If the crash loop stops, migrate your data using Migration Assistant

Step 5: Reset NVRAM/PRAM and SMC

• Intel Macs: Restart and hold Option + Cmd + P + R for 20 seconds
• Apple Silicon (M1/M2): NVRAM reset not required; just restart
• Reset SMC (Intel only): Shut down, press Shift + Control + Option on left side and power button for 10 seconds, then release all and power on

Alternative Fixes

• Safe Mode: Boot into Safe Mode (hold Shift during startup) to load only essential kernel extensions. If the crash stops, a third-party extension is likely the cause.
• Reinstall macOS: Use Recovery Mode to reinstall macOS without erasing data. This replaces system files while preserving user data.
• Check for macOS Updates: Go to System Settings > General > Software Update and install any available updates, as Apple often patches launchd bugs.
• Third-Party Cleanup Tools: Use tools like Onyx or EtreCheck to identify and remove problematic launch agents.

Prevention

• Regularly update macOS to avoid known launchd issues.
• Avoid installing unnecessary third-party launch agents; review permissions before installation.
• Monitor Console.app periodically for unusual launchd activity.
• Back up plist files before editing or deleting them.
• Use Time Machine to create regular backups so you can restore system files if needed.

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 visit an Apple Store for further diagnostics.