Error code

macOS -34

MACOS-34
System Error Code· A POSIX/system errno returned when a system call fails.

What it means

Disk full (dskFulErr) — the destination volume has no remaining free space..

How to fix it

  1. Empty the Trash.
  2. remove large or duplicate files via Finder > About This Mac > Storage > Manage.
  3. move data to an external drive.
  4. clear system caches with a Safe Mode boot.

Not affiliated with macOS. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.