Ok. I just installed Blender 2.91. I have been very eagerly awaiting this mainstream release, and now find out that my custom startup / UI settings were not retained. Weirdly, it also vapourised my recent files list, back to sometime in September!
How do I get around this problem? When I roll back to 2.90.1, those things are still there, so the information is still being retained on the drive somewhere and thus is still available. I just want this to work, you know? More specifically, I want to fix this and just get back to work…