Eric,
Thanks for replying.
Inside my Library folder is a folder called Mail. In the Mail folder is a folder called V2 and inside V2 is a folder called:
IMAP-{gmail email address}@map.gmail.com which is 29.7 GB
another called IMAP-{secondary gmail address}@map.gmail.com which is 1.6 GB
I assume each folder is for the two email accounts. I didn't think it safe to broadcast my email address in public.
In the other User Account Library the V2 folder contains a similar IMAP xxxxxx folder which contains 31.2 GB
If I check my Google Mail via the web interface it tells me I have used approximately 11 GB. I forgot that deleting a message in Mail doesn't delete it in Google Mail.
I thought the size of the V2 folder might have something to do with my problem, but it appears that is not the case.
I have also taken other advice to delete the envelope files which cause the database to be rebuilt and that didn't help either.
Any help you could offer would be greatly appreciated. My system was extremely stable until I upgraded to OS 10.8.5 so I could use Lightroom 6 since Apple has stopped supporting Aperture. It's one of those "shaggy dog stories."
Sincerely,
Roy Patience