How to delete four non existing folders "Default"?

In Tools --> Status of syncronization there are four folders “Default” with no notes. I cannot find them with the search-button or manually.


Is there a way to delete them?

This is quite strange. I’m assuming these are notebooks without parents so they don’t appear anywhere. Are you certain they are not somewhere as a sub-notebook?

Yes, I checked it once again. No Default folder or subfolder is available.

(Is there a database tool available, which I can use? Or call a script or so? Or can Joplin reorganize the database?)

I remember @merlinuwe dragged notes to the Notebooks folder (which is not a folder) and the notes vanished. Maybe this current behavior has something to do with that.