Lightroom 5.1 stuck at startup half of the time

Version: Lightroom 5.1 on Windows 11

When I open Lightroom, half of the time the app starts but doesn't display any photo, most of the menus are greyed out and if I look at my settings I notice that information related to my cloud quota & such are not available. The app is not frozen, I can click on menus, it's just missing the content. The app seems to be doing something (some CPU activity, not a lot of network usage), but it'll happily stay in that state for alonger than I left it running (30 minutes?) If I restart it, it might just load all the content in seconds.

Any idea what's going on?