I switched to a different Photos library (on a different hard drive), and all of a sudden FCPX doesn't let me browse that library when I'm trying to import video. It instead says "Open Photos to see your photos in this list" (it's already open).
It seems FCPX still thinks I'm using the old library (some of my events/vids use clips from the old library, which are now marked as missing). How can I fix this? I'm tried uninstalling/reinstalling FCPX according to the official instructions, but no luck.