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

Symptoms

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

• Repeated crash reports in Console app under user launchd processes.
• System sluggishness, especially after login.
• High CPU usage by launchd or related user agents.
• Frequent pop-ups or beachball cursors.
• Crash logs filling ~/Library/Logs/DiagnosticReports/.

Root Causes

The com.apple.launchd.peruser process is responsible for managing user-level daemons and agents. A crash loop occurs when one or more user launchd plists are corrupted, misconfigured, or incompatible with the current macOS version. Common triggers include:

• Third-party software (e.g., Adobe, Dropbox, or antivirus) with faulty plist files.
• Incomplete macOS updates or upgrades.
• Corrupted user preferences or cache files.
• Permissions issues on ~/Library/LaunchAgents/ or /Library/LaunchAgents/.

Step-by-Step Fix

1. Identify the offending plist

1. Open Console app (from /Applications/Utilities/).
2. Search for 'launchd' or 'peruser' in the search bar.
3. Look for crash logs showing a specific plist path (e.g., com.example.agent.plist).
4. Note the exact plist filename causing repeated crashes.

2. Disable the problematic plist

1. Open Terminal.
2. Run: launchctl unload -w ~/Library/LaunchAgents/com.example.agent.plist (replace with your plist).
3. If the plist is in /Library/LaunchAgents/, use: sudo launchctl unload -w /Library/LaunchAgents/com.example.agent.plist.

3. Remove or repair the plist

1. Move the plist to a backup location: mv ~/Library/LaunchAgents/com.example.agent.plist ~/Desktop/.
2. Alternatively, open the plist in a text editor (e.g., Xcode or TextEdit) and verify its XML structure. Look for missing keys like Label or ProgramArguments.
3. If corrupted, replace with a clean version from the software vendor.

4. Clear launchd cache

1. In Terminal, run: sudo launchctl reboot userspace (requires macOS 10.10+).
2. Alternatively, restart your Mac normally.

5. Verify permissions

1. Run: sudo chown root:wheel /Library/LaunchAgents/*.plist (if applicable).
2. For user agents: chmod 644 ~/Library/LaunchAgents/*.plist.

Alternative Fixes

• Safe Boot: Restart while holding Shift to load minimal launchd items, then remove suspicious plists.
• Create a new user account: Test if the crash persists. If not, migrate data to a new user.
• Reset NVRAM/PRAM: Restart and hold Option+Command+P+R for 20 seconds.
• Reinstall macOS: Use Recovery Mode to reinstall without erasing data.

Prevention

• Keep macOS and all third-party software updated.
• Regularly review ~/Library/LaunchAgents/ and /Library/LaunchAgents/ for unknown plists.
• Use Activity Monitor to monitor launchd CPU usage.
• Before installing new software, check for known compatibility issues with your macOS version.
• Maintain regular backups with Time Machine to restore corrupted plists if needed.

By following these steps, you can eliminate the com.apple.launchd.peruser crash loop and restore system stability. If the issue persists after all steps, consider contacting Apple Support or the software vendor for further assistance.