since I did reorganize all my Notebooks and made some changes to them, the above error code shows up.
I do run Mac OS the newest version, Joplin 2.7.13. On the Mac it is a fresh installation with out any plugins.
On my Notebook that runs under Windows 10, Joplin 2.7.13 with some plugins. No fresh installation and around over 100`000 Nots and also over 500 folders and subfolders and subsubfolders