DIM Weirdness
Well, this is new:
DIM is listing my entire purchase history in the 'Ready to Download' column, and nothing in the 'Installed' column. The directories are correctly set in the settings, and everything seems to be fine as far as the actual installations (everything still works in Studio) but DIM doesn't seem to know that. Uninstalled DIM and re-installed DIM, but same issue. Any suggestions?

Comments
DIM relies on the "manifest files" stored in the "manifest archive" folder to know what was installed and when. Are those files present?
Hey, that did it. I apparently moved the folder accidentally the other day and didn't realise it. Thanks so much!