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

Symptoms

• Repeated pop-up notifications stating that a process has crashed, often referencing com.apple.launchd.peruser.
• System becomes sluggish or unresponsive, especially after login.
• Console logs show repeated crash entries for user-level launchd processes.
• Applications may fail to launch or behave erratically.
• High CPU usage by launchd or related processes in Activity Monitor.

Root Causes

Corrupted User Launch Agents

User-specific plist files in ~/Library/LaunchAgents can become corrupted, causing launchd to crash repeatedly when trying to load them.

Third-Party Software Conflicts

Some applications install launch agents that are incompatible with the current macOS version, leading to a crash loop.

User Session Issues

Problems with the user account, such as corrupted preferences or permissions, can cause peruser launchd to fail.

System Updates

Incomplete or failed macOS updates may leave launchd configuration files in an inconsistent state.

Step-by-Step Fix

1. Boot into Safe Mode
   Restart your Mac and hold the Shift key until the login window appears. Safe Mode loads only essential kernel extensions and disables user launch agents. If the crash stops, the issue is likely with a user launch agent.
2. Check Console Logs
   Open Console app (/Applications/Utilities/Console.app). Search for launchd and peruser. Note any specific plist files mentioned in the crash logs.
3. Disable User Launch Agents
   In Terminal, run: launchctl list to see all user agents. Then unload suspicious ones using launchctl unload ~/Library/LaunchAgents/<filename>.plist. Alternatively, move the plist files to a backup folder: mkdir ~/Desktop/backup_agents && mv ~/Library/LaunchAgents/*.plist ~/Desktop/backup_agents/.
4. Reboot Normally
   Restart your Mac normally. If the crash loop stops, the problem was with one of the disabled agents. Re-enable them one by one to identify the culprit.
5. Repair Disk Permissions (Older macOS)
   For macOS versions prior to Catalina, use Disk Utility First Aid or diskutil repairPermissions / in Recovery Mode.
6. Create a New User Account
   Go to System Settings > Users & Groups > Add User. Log into the new account. If the crash loop does not occur, the original user profile is corrupted.
7. Reset NVRAM/PRAM
   Shut down, then turn on and immediately press Option + Command + P + R for 20 seconds. Release and let the Mac restart.

Alternative Fixes

• Reinstall macOS via Recovery Mode (Command + R at startup). Use Reinstall macOS without erasing the disk.
• Use Onyx (free utility) to clean system caches and rebuild launch services database.
• Check for Malware using Malwarebytes or similar tools, as some malware installs persistent launch agents.

Prevention

• Keep macOS and all third-party software updated to the latest versions.
• Regularly clean out unused launch agents from ~/Library/LaunchAgents.
• Create regular backups with Time Machine to restore a healthy user profile if needed.
• Use Activity Monitor to monitor launchd CPU usage and investigate any anomalies early.

Additional Resources