Gmail duplicate folder name error. “J12 NO [ALREADYEXISTS] Duplicate folder name (Failure)”

It appears MailMate tries to create a mailbox that already exists, but for some reason MailMate does not know this. In any case, MailMate should not be trying to create this mailbox at all if it's a Gmail account.

Try this:

1. Under SOURCES in the mailbox outline, locate “[Gmail]/Trash” (it might be named differently depending on your language). Check in the Mailbox menu that the “Mailbox Type” is “Deleted Messages”.
   
2. Locate “Deleted Messages” under SOURCES
   ▸ “Your Gmail Account”. If it contains messages then move them to “[Gmail]/Trash”. When it's empty use the Mailbox menu to “Delete Mailbox”.

Now try taking the account online again.

If you do not see any “[Gmail]/Trash” mailbox then check your webmail settings and make sure the mailbox is available via IMAP. You might also want to check “File ▸ Edit IMAP Account ▸ Your Gmail Account” and click on “Subscriptions”.

I hope this helps.

Thanks so much. I fixed this by deleting the "deleted messages" folder in the gmail web client, and changing the name of the other problem folder.
Thanks again
C