[birkmaggs]

I have thousands of ebooks scattered across several hard drives.

Many have not been entered into Calibre

Is there a utility that will scan my hard drives, determine if the book is in my catalog, and enter it automatically, or at least produce a list and I can peruse to decide if I want it entered?

It would not have to be specifically Calibre related, just something that can look at the books in my calibre directory and test them against everything else.