The same thing just happened to me for the second time - everything in my movies folder (which is on a drive pool comprised of 5 12TB drives) is missing, roughly 1800 movies and 20TB.
The first time this happened I chalked it up to some sort of user error, though never could figure out what happened. However, once again, it has now happened again. Reading through this thread it is clear that there is some reoccurring problem. I am attaching my logs, but it also seems clear that logs do not capture this, per the above chain. Logs: https://drive.google.com/file/d/1BHSHqcKfagsPQqKqHwaISlUigiFjahK9/view?usp=sharing
@anon18523487, I am happy to help cooperate in figuring this out in any way possible. I love Plex, but at this point am nervous about continuing to use it, despite having paid for a lifetime membership.