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

Symptoms

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

• High CPU usage caused by repeated launchd process crashes and restarts.
• System sluggishness, fan noise, and reduced battery life.
• Repeated error messages in Console.app such as: com.apple.launchd.peruser.501: (com.apple.launchd.peruser.501) Exited with code: 1 or com.apple.launchd: (com.apple.launchd.peruser.501) Throttling respawn: Will start in 10 seconds.
• Some user-level services or agents may fail to start properly.

Root Causes

The crash loop typically originates from one or more of the following:

• Corrupted or misconfigured user launchd plist files in ~/Library/LaunchAgents/ or /Library/LaunchAgents/.
• Third-party software that installs unstable launch agents or daemons.
• Incorrect file permissions on launchd plist files or the launchd database.
• System-level launchd issues after macOS updates or partial upgrades.
• Malware or adware that injects persistent launchd entries.

Step-by-Step Fix

1. Identify the Problematic Plist

1. Open Console.app (from /Applications/Utilities/).
2. In the search bar, type launchd.peruser.
3. Look for recent error messages. Note the process name or plist path mentioned (e.g., com.example.agent.plist).

2. Disable or Remove the Faulty Agent

1. Open Terminal.
2. Unload the agent:

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

   Replace with the actual plist name.
3. Move the plist to a backup location:

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

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

3. Check and Repair Permissions

1. Run:

   sudo chown root:wheel /Library/LaunchAgents/*.plist

2. For user agents:

   chmod 644 ~/Library/LaunchAgents/*.plist

3. Repair disk permissions (macOS Catalina and earlier):

   sudo diskutil repairPermissions /

   For Big Sur and later, use First Aid in Disk Utility.

4. Reset Launchd Database

1. Boot into Recovery Mode (restart and hold Command+R).
2. Open Terminal from Utilities menu.
3. Run:

   launchctl reboot userspace

4. Alternatively, remove the launchd cache:

   rm -f /var/db/com.apple.launchd.peruser.*

   Then restart.

5. Scan for Malware

1. Use Malwarebytes or KnockKnock to scan for persistent launchd entries.
2. Remove any suspicious agents found.

Alternative Fixes

• Create a new user account to test if the issue is user-specific. If the crash stops, migrate data to the new account.
• Reinstall macOS via Recovery Mode as a last resort if the issue persists system-wide.
• Use EtreCheck to generate a system report and identify problematic launchd items.

Prevention

• Only install software from trusted sources (App Store or reputable developers).
• Regularly review launch agents in ~/Library/LaunchAgents/ and /Library/LaunchAgents/.
• Keep macOS and all software up to date.
• Use a firewall and anti-malware tool to prevent unwanted persistent processes.

By following these steps, you can resolve the com.apple.launchd.peruser crash loop and restore normal system performance.