OK, this is a weird one. I have a drive with two folders in the root directory. Folder 1 is roughly 1.1TB and Folder 2 is about 500GB. Yesterday, Folder 2 vanished. It wasn't deleted or moved to a different location - it just isn't there any more. Now, total used space for that drive is still showing approximately 1.6TB, but the only folder is Folder 1 with 1.1TB showing. So, there is about 500TB of not data on the drive. Folder 2 isn't hidden - I checked for hidden files - so the data should still be there. I've tried numerous recovery apps and none of them can find anything, presumably because the files were not actually deleted. Drive health is fine, there's no encryption/permissions on there. None of this is important - the data in that folder is backed up and only maybe a couple of files are lost, but can be recreated easily. This isn't about that. It's just seriously twisting my frikkin noodle and I want to find out how it happened. Any ideas?