You probably know where this is going. I spent a marathon JOSM session editing the roads and features in and around Little Ocmulgee State Park. It was a case of "Just one more edit" that ran well over an hour. When I went to save . . . well, there hangs the tale. As often happens, there's various errors and warnings that JOSM catches. Unfortunately, the ones from this session were not so easily resolved. Now, if I had saved after each edit, it would be a simple matter of using undo. But no: These errors were buried so deep that undo was out of the question. After various attempts at repair that only made things worse, I just put it out of it's misery. I deleted the edits.

Lesson for today: Save often enough that you don't lose an entire session when errors strike.