Adobe Reader DC won't save preferences

The threads on this topic are pretty old, so I'm going to try again, since nothing worked.

The right pane on documents opens with every document, and the document opens in full screen.  I've changed this before, but after an update, everything's back and it will not save. As soon as I close the document and reopen it, the right pane is open again and the document is once again in full screen.

My compatability settings are all turned off, and these documents are recent.  I just updated to version 2021.005.20060.  I actually tried turning compatability on but that didn't help so it's off again.