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

Symptoms

• Repeated crash reports for com.apple.launchd.peruser in Console.app.
• High CPU usage by launchd or kernel_task.
• Slow system performance and unresponsive applications.
• Users may see pop-ups about applications unexpectedly quitting.
• System logs show recurring entries like com.apple.launchd.peruser: (path) exited with code: 1.

Root Causes

1. Corrupted or misconfigured launch agent plist files in ~/Library/LaunchAgents, /Library/LaunchAgents, or /System/Library/LaunchAgents.
2. Third-party applications with faulty launch agents (e.g., outdated software, malware).
3. Incomplete macOS updates or permission issues.
4. User profile corruption causing launchd to repeatedly attempt to load invalid agents.
5. Conflicts between user and system launch agents.

Step-by-Step Fix

1. Identify the Faulty Launch Agent

1. Open Console.app (from /Applications/Utilities).
2. Search for com.apple.launchd.peruser in the logs.
3. Note the path of the plist file causing the crash (e.g., /Users/username/Library/LaunchAgents/com.example.bad.plist).

2. Disable or Remove the Problematic Plist

1. Open Terminal.
2. Unload the agent (replace path/to/plist with the actual path):

   launchctl unload ~/Library/LaunchAgents/com.example.bad.plist

3. Move the plist to a backup location:

   mv ~/Library/LaunchAgents/com.example.bad.plist ~/Desktop/

4. If the plist is in /Library/LaunchAgents, use sudo:

   sudo launchctl unload /Library/LaunchAgents/com.example.bad.plist
   sudo mv /Library/LaunchAgents/com.example.bad.plist ~/Desktop/

3. Clear Launchd Cache and Reboot

1. In Terminal, run:

   sudo launchctl reboot userspace

2. Alternatively, restart your Mac normally.

4. Verify Fix

• Check Console.app for new crash entries.
• Monitor CPU usage in Activity Monitor.

Alternative Fixes

• Safe Mode: Boot into Safe Mode (hold Shift during startup) to disable third-party launch agents temporarily.
• Create a New User Account: If the issue is user-specific, create a new admin account and migrate data.
• Reset Launch Services Database: Run sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.launchd.plist (advanced).
• Reinstall macOS: As a last resort, reinstall macOS without erasing data.

Prevention

• Regularly update macOS and third-party apps.
• Avoid installing untrusted software that may add launch agents.
• Periodically review ~/Library/LaunchAgents and remove obsolete plists.
• Use Activity Monitor to detect unusual launchd activity early.
• Back up plist files before modifying them.

By following these steps, you can eliminate the com.apple.launchd.peruser crash loop and restore system stability. If problems persist, consider contacting Apple Support or an authorized service provider.