Error code

macOS -50

MACOS-50
System Error Code· A POSIX/system errno returned when a system call fails.

What it means

Parameter error (paramErr) — an invalid or out-of-range value was passed to a system call..

How to fix it

  1. Restart the Mac.
  2. reset NVRAM by holding Option+Command+P+R at startup.
  3. run Disk Utility First Aid.
  4. copy via Terminal instead of Finder.
  5. rename the file if it contains special characters.

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