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

Symptoms

• Repeated pop-ups or system logs showing "com.apple.launchd.peruser" crashing
• High CPU usage by launchd processes
• System instability, slow performance, or unresponsive apps
• Console logs filled with "exited with code: 1" or "signal: 6" for user agents

Root Causes

1. Corrupt or misconfigured user LaunchAgent plist – A plist file in ~/Library/LaunchAgents/ or /Library/LaunchAgents/ may have syntax errors or reference missing executables.
2. System file corruption – Damaged system files or permissions can cause launchd to fail.
3. Third-party software conflicts – Antivirus, VPNs, or system utilities may interfere with launchd.
4. Hardware or NVRAM issues – Rarely, corrupted NVRAM or SMC settings cause instability.

Step-by-Step Fix

Step 1: Identify the Culprit Plist

1. Open Console app from /Applications/Utilities/.
2. In the search bar, type launchd and filter by Errors and Faults.
3. Look for messages like (com.example.app) Exited with code: 1 – note the label (e.g., com.example.app).
4. Search for that label in ~/Library/LaunchAgents/ and /Library/LaunchAgents/ to find the plist.

Step 2: Disable the Faulty Plist

1. Open Terminal.
2. Backup the plist: cp ~/Library/LaunchAgents/com.example.app.plist ~/Desktop/
3. Remove it: rm ~/Library/LaunchAgents/com.example.app.plist
4. Unload if currently loaded: launchctl unload ~/Library/LaunchAgents/com.example.app.plist
5. Reboot and check if crashes stop.

Step 3: Repair System Permissions (macOS Catalina and earlier)

1. Boot into Recovery Mode (Cmd+R at startup).
2. Open Terminal from Utilities menu.
3. Run: diskutil resetUserPermissions / $(id -u)
4. For system permissions: diskutil repairPermissions / (if available).

Step 4: Reset NVRAM and SMC

• Intel Macs: Shut down, then press Option+Cmd+P+R at startup for 20 seconds. For SMC, see Apple support.
• Apple Silicon (M1/M2): NVRAM reset is automatic; shut down and wait 30 seconds.

Step 5: Safe Mode Boot

1. Restart and hold Shift key until login appears.
2. In Safe Mode, launchd loads only essential plists. If crashes stop, a third-party plist is the cause.
3. Exit Safe Mode and systematically disable plists in LaunchAgents folders.

Alternative Fixes

• Create a new user account – If crashes are user-specific, migrate data to a new account.
• Reinstall macOS – Use Recovery Mode to reinstall without erasing data (preserves files but replaces system files).
• Use EtreCheck – Third-party tool to scan for problematic launch agents and system issues.

Prevention

• Regularly update macOS and all third-party software.
• Only install trusted apps from the App Store or verified developers.
• Periodically review and clean LaunchAgents folders using Terminal or tools like LaunchControl.
• Maintain regular backups with Time Machine to quickly revert if a plist causes issues.

Additional Resources

For further details, consult Apple's official documentation on Console and launchd plist creation.