[PacificNW]

Instead of deleting the file "metadata-sources-cache.json" I set it to be a zero-byte-sized file.

Now it all works again.... even repeatedly through calibre restarts, etc.

BUT... a strange BUT.....

When I download metadata for popular titles, now they are almost always for the audiobook versions of the books [I don't use audiobooks].

Have NEVER, over years of use, seen this happen.

So the fix is still partial, but liveable for now.

EDIT: I also tried a two-byte file, containing an empty JSON dataset {}. This also works.