When I SHARE a video from FCP, or send to Compressor to share, the exported video freezes in the last few seconds. Instead of fading out, the video freezes about 5 seconds before the end, while the sound still plays to the end.
I have tried deleting all the render files and also deleting preferences, which works at first, but the problem keeps coming back. Very frustrating.
Running FCP 10.4.6 on a 2010 Mac Pro, with 10.13.6 High Sierra
1st, turn off background rendering (causes more problems than it solves IMHO). Select the Library itself in the Browser. Go to the Edit menu, to Delete All Generated Files for the Library. Delete ALL render files. Try again.
Another thing that works sometimes, find the clip the video freezes on. Do replace edits for that clip and everything to the end, since you're near the end. Then delete all render files.