Started the app -- and saw nothing but the Joplin main menu (File | Edit | etc). Restarted the app: same result. Meanwhile Joplin on my android phone is just fine, and shows my usual list of notes.
I fixed it, but I'm wondering why it would happen at all, and if others experienced it too.
The only significant recent change to my laptop I can think of is that ~2 days ago the Win 11 "24H2" update applied itself. This update doesn't seem to have had a negative effect on any of my other many apps.
Tried a few minor Win troubleshooting steps... and [View | Reset application layout]... but the fix was to uninstall Joplin app + reinstall (from Joplin website). [shrug] Started the app, and boom, all my notes and normal Joplin screen elements appeared as they should have before.
Yes with my W11+Joplin 3.3.4 portable version.
When there's not enough space on my system disk (even though my joplin datas are on an external disk with enough space) I have exactly the same symptoms.
Maybe the windows update had used a lot of space on your systemp disk... Before to be definitively installed. The update create a lot of temporary files...