That screen shot makes debugging a lot easier.
First, I assume that the screen shot is of a calibre library and not a backup folder. If so, then the number in parenthesis is the calibre database ID for that book, at least when the book was created. If check library does not report that one of (for example) Grailblazers with ID 213 or 1331 is extra, then there is every reason to believe that records exist in calibre's db with those ids.
Fortunately it is easy to search in calibre for a book with a given id. Using Grailblazers again as an example, the two search expressions are:
or if you want them both at once:
Code:
id:=213 or id:=1331
The result of the search should be one or two books, at which point you can look at the metadata for them.