macOS error codes come from several overlapping frameworks — Carbon, Cocoa, CoreServices, and the POSIX layer. Below are the most frequently encountered codes with fixes you can apply immediately.
Error Codes
| Error | Description | Fix |
|---|---|---|
| Error -36 (ioErr) | Input/output error — disk read failure or filesystem corruption | Run Disk Utility First Aid, check cables, and verify the disk with diskutil verifyVolume |
| Error -43 (FNFErr) | File not found — the requested file or alias cannot be located | Check the file path, resolve broken aliases, and verify the file exists in Finder |
| Error -50 (paramErr) | Parameter error — invalid argument passed to an API or command | Verify command arguments, check for null values, and review API documentation |
Quick Diagnosis
Run these commands on macOS to gather error context:
# Read the system log for recent errors
log show --predicate 'eventMessage contains "error"' --last 1h
# Check Keychain access
security list-keychains
# Run diagnostics
diagnose