iMovie Not Enough Disk Space

Try these three procedures and see if one of them cures the problem.

Boot up in Safe Mode (see Finder menu for instructions) and, after everything loads, immediately shut down and reboot in normal mode. Then see if iMovie works properly.

Try resetting the System Management Controller (but no longer available for the new M1 computers):

https://support.apple.com/en-us/HT201295

Try resetting the NVRAM or PRAM:

https://support.apple.com/en-us/HT204063

-- Rich

You have tried the usual procedures to address the problem. Since still no luck, try contacting Apple Support.  The techs there have the capability of remotely accessing your computer that we cannot do here.  To contact apple support click on the Get

Support item in the upper right hand corner of this forum’s screen.  Navigate to a place where you can enter your phone number.

-- Rich

What is the exact wording of the error message? Can you post a screen shot of it?

What is the format of the video clips you are trying to import into iMovie?

-- Rich