Find and remove un-indexed files from library folder

[eater]

After a colleague's failed tagging adventure while I was away, I now have hundreds of duplicates of PDF files in various folders under my library folder. However, Calibre is unaware of the existence of the duplicates.

What I'd like to do is generate a list of all the files Calibre has indexed -- including their file paths -- so that I can compare and then delete the ones that are NOT in that list.

How can I do that? Or is there a better way to fix this?

[theducks]

Simpler way: Move the Known books to a new Library, then deal with what is left behind

Create a new Library is simple
Liick On the Library Icon : Create/switch: Create a new Library and TICK the Copy Structure box (Make-Pick an empty folder. That will also be the new Library name)
When that is done: Switch back to the original Library (the name will be on the quick switc plar of the Library Icons list:
Select ALL BOOKS (ctrl-A): Right-click:Copy to Library:New one name (delete)
And let it grind (the time varies on how many books):
When that is done, the Library will appear to be empty. Switch to the New one.

Now Using the OS (eg Explorer) find your old Library folder (Calibre Library is the default name). What is there is your problem guys Use CALIBRE or Drag and drop titles onto the Calibre GUI.
DO NOT do that wit metadata.db or the JSON file

[eater]

Thanks!