I know Kiwidude is no longer active, but if anyone wants to look at this problem I'll be grateful.
When I search for duplicates in another library using the identifier set as URL it doesn't find anything even though I know there should be multiple duplicates. It says:
Code:
calibre, version 3.6.0
Library Duplicates: Found <b>0 books</b> with potential duplicates using <b>matching 'url' identifier</b> against the library ...
Can anyone help?