I am using the following setup:

  • macOS Big Sur 11.2.3
  • QuickTime Player 10.5
  • MacBook Pro (M1, 13-inch, 2020)

I've compressed an MP4 movie file in QuickTime Player Version 10.5.

When I try to export the compressed file, I get the following error below:

“The operation could not be completed An unknown error…”

What would cause this error? How can it be solved?

enter image description here

  • 1
    Where are you trying to save it?
    – Tetsujin
    Commented Nov 7, 2022 at 16:38
  • 1
    I have tried to save it under two directories. One is Document and second is Desktop
    – amstriker
    Commented Nov 7, 2022 at 18:30

1 Answer 1


Quit QuickTime Player and try clearing preferences. You can do this by navigating to ~/Library/Preferences and removing the com.apple.QuickTimePlayerX.plist file.

Commander One simplifies file operations on macOS. Try using it for managing your video files and see if the issue persists.

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