Yesterday I updated from 64-bit Calibre 2.13.0 to 2.21.0 (using Win7 on a Dell) and now find that Edit Metadata in Bulk does not work, even for very simple changes, although I can Edit Metadata on single ePubs.
When I try to use the edit bulk approach for a selection of books, everything seem to go normally but after I click on "ok" the data simply does not change. I tried even very simple match and replace bulk edits (using both character match and regular expressions) but nothing works.
Strangely enough, after I first installed the 2.21.0 update, I used the Edit Metadata in Bulk twice and it worked fine, but the third and subsequent times I tried it, it no longer worked.
This paragraph may be a clue to the problem or just an over-complicated red herring, so maybe ignore it for now if info in other paragraphs is sufficient: The only other anomaly that comes to mind is that after doing the update to 2.21.0, the first time that I tried to isolate a selection of books as a virtual library (specifying "current search" I think, as alway) I was prompted to name the virtual library. That had never happened before (I labelled it "temp"), but it's possible that I atypically clicked on "Create Virtual Library" (although I've never done that before) rather than "current search", since I was thinking of the new feature in 2.21.0 whereby edits within the tag browser can now be restricted to a selected virtual library. I then proceeded to isolate a different selection of books as a different virtual library (using "current search", with no prompt to name this virtual library) and then successfully performed the two bulk metadata edits referenced above. HOWEVER, then I decided to delete the previously-created "temp" virtual library since I would not need it later, and I think it was THEN that I was no longer able to do any more bulk metadata updates, even after re-boots, etc.
I also considered that the timing of the Calibre update was just a coincidence and maybe I was encountering some capacity limits because, over time I have gradually added more user-defined (30+) columns, including 3 more that I recently added. So as a test I deleted six of the columns that I am no longer using, and still find the metadata bulk edits do not work.
I have tried re-running the 2.21.0 update using the "repair" option, but it did not correct the problem.
I thought I would see others complaining about the problem, but that hasn't happened so maybe there is something unique in my circumstances.
Thanks in advance for any suggestions, or comments from others who might see if they now have the same problem.