So my microsoft office365 email account that I access with Thunderbird is almost full (think 100,000 messages), and I would like to move those messages off of the server and into local folders as backup. I've done this in the past and, while it would be cumbersome and slow, it would eventually work. Now though, I can't seem to move more than 5-10 messages at a time to a local folder. That isn't helpful with so many emails to process! When I try larger batches, the program just balks, no error message, no emails moving, just nothing. In the past the emails would move, but then it would take ages for the mail server to catch up. Now it just isn't trying. Any help would be appreciated!