[At_Libitum]

Every file is still in place, it's a local drive, passes chkdsk and several other. No links or shortcuts in the library, no humongously long names (did an expand all on the top level folder.


The Y:\0 folder I created in the root I created by letting Calibre create an empty library, then I copied the contents of the Y:\Books\Transfer folder, so basically all of the subfolders but not the metadata.db and metadata_db_prefs_backup as these are likely corrupted anyways if the booklist is empty. All of the books still have their opf files present in their associated folders.

Just for kicks I created again a 1 character long folder in the root. Copied in just one author folder with 1 book folder (and everything there, .opf, cover, epub)
Andre Kyte - The Hidden Realm

same result. same error about the path having to be < 89

All of the test library folders created in the process where created by creating a blank library copying the structure of an existing one (which passes all of the Calibre checks)

Sorry, I ain't going to waste an evening hunting this down. There's clearly an obscure situation where during a batch move files do not get moved due to an external system error (windows error 5) but the booklist still got emptied as if they were moved. And Restore not working...I'll just lift out all of the books in a search and will dump them on a new empty lib, less aggravation from having to recreate missing metadata as from having to figure why a 1char long libfolder name can possibly be too long, and author/title folders? Well Calibre made these itself so if there's no bug in that part of the code, these could not be too long as this would have violated it's own length limitations.

EDIT: And I also just did a check if there weren't any remnants from exploded epubs left behind from Tweak/Modify. None found so that ain't causing a length violation either