I have a Mac Mini (Mid-2011 model), running Mac OS X 10.11.6, with iMovie 10.1.6.
I have a
iMovie Library.imovielibrary file in the
~/Movies folder, which contains all my iMovie projects.
When I don't have iMovie running, and I perform a Time Machine backup, Time Machine backs up the file just fine.
However, when I have iMovie running, Time Machine does not back up the file. For some reason, Time Machine believes the iMovie Library file has been deleted, while iMovie remains open. And then when I quit iMovie, Time Machine backs up the iMovie Library file again, since it is then able to "see" the iMovie Library again, even though it never went anywhere.
And since Time Machine thought the iMovie Library was deleted, then later sees it, it thinks that the iMovie Library is new, so it backs the whole thing up, rather than only the changes that were made since the last iMovie Library backup.
So, why does Time Machine believe that the iMovie Library is deleted while iMovie is open, and how can I fix it? I've already tried running
First Aid on my internal drive, but that didn't fix it.