@JonMikelV Thanks for responding and giving hope to resolve this issue.
Since a few minutes ago the issue is resolved.
I think it went like this.
When I tried to delete the backup I got error messages stating I could repair. I followed the advise offered in these error messages, got other error messages, tried deleting, purging (and others) and even added the “–allow-full-removal” option. But I lost sight of the original command.
All this while gathering the information for your 6 questions. Then I read your note on “same destination folder” and realised that is what I am doing because the backups are on a raspberry pi 3 with an external hard disk attached and the target is the same folder as the other well working backup.
- yes, about the X number of remote files that are not recorded in local storage, please run repair.
- GUI
- 2.0.2.1
- Tray icon
- windows 10
- raspi3 external HD by SSH.
After fiddling around I suddenly saw the delete option again and tried it anew. It worked!
And I learned that each backup should go into its own folder 
Thanks.