Somehow I fixed it...
Deleting almost all account files in User\AppData didn't work this time. Seems to be an issue of the cloud file/folder-structutre to me.
So to the solution:
- I opened my "first project" on the web (from within fusion). Note: I did so with my new work-account as my private account has basic access only right now but is the "owner" of the "first project" that causes the issue.
- I created a new folder inside my "first project" (which I renamed long ago). The new folder is now owned by my work-account (I still try to figure out what happens to folders n files if an accout gets deleted/lost though).
- Then I moved my first ever crated file from the old folder into the new folder (and left the old folder empty for now).
- Back in Fusion I then navigated to my current project. I did not refresh the data panel as asked in the pop-up but closed the pop-up insted (clicking the x).
- I closed Fusion and restarted it. The data panel did not open in my current project but at the home screen so I navgated to my current project and closed Fusion again.
Now when I open Fusion it finally remembers where I've been working... The nuber of issued I had with the data panel in the past years is a shame!