Same problem here. I have several internal drives, and made some events and projects on some of them. Could edit really nicely, and closed FCPX at the end of the day.
Next day, the events show up for as long as the FCPX splash screen is visible, then they disappear. Projects are fine, likewise the event folder structure looks intact on the drive. Very strange.
Tried the tips from people who had their external drives not showing up (checking journaling, permissions, renaming files with “video” in them, deleting old mp4 files etc). Nothing works.
Deleted Perian, WMV Player etc.
Very, very frustrating, as the FCPX workflow seems to be very good for me. Would really like to continue learning.
Cheers,
Rabbe