I am trying to import MOV files from a USB disk -- into iMovie's event library. When I click on the files on the USB -- they are grey and won't import. They will play in QuickTime. What could the problem be? I have the latest OS and am up to date.
Can you maybe try converting them? Download the free program called Miro Video Converter from the Mac App Store. Drag the video into the window and set the output format as mp4. iMovie should import that properly.