I deleted the files within the calibre software - not in my collection folder and not directly in the library folder. I clicked on one file and pressed "DEL" on the keyboard. The file was gone from the list, as it was supposed to be. It was gone from the library file, again as expected. It was still there in the original folder it came from. Therefore I felt rather safe in deleting more files from within the calibre software.
And I need the empazise again that yesterday before I shut down my machine all files where there in my personal collection folder. I did not delete them in any form. The recyle bin is empty, I already tried a recovery programm which didn't found anything. The disk space on my drive is still as it should be. I check those daily, so I know. And a 50 gb chunk of disk space suddenly added I would notice. And working with calibre was all I did yesterday.
Look, I am not an idiot. I use computers since the 1980s. I am well aware I might have done some mistake I just can't figure out where. Like I said, I checked before deleting 100s of files from calibre. I deleted the software because I hoped that maybe there was a registry entry or something like that which was responsible. Was that hasty ? Probably. But I can still see all my files in WizTree (
https://wiztree.en.lo4d.com/windows).
I could understand if the files I deleted from within the calibre software were gone from both folders, but they are all gone from within my collection folder. Safe from about 30 books in one subfolder which I again have no clue why those were left.
It just doesn't make sense one way or the other.