We couldn't create the Outlook data file. Make sure the disk you're saving to isn't full or write-protected and that the file isn't being used.
This is bogus. Actually in this case there was a Google Account setup that wasn’t working. We removed it from Send / Receive groups and then suddenly we could add the account.
So, no, your disk is not full but it’s easy to check.
And no, there is no write protection. What a load of crock.