<blockquote> Is it best to do this through the Profile and if so how? </blockquote> I have no idea what 'through the Profile' means. You'd need to backup your entire email archive on Gmail as long as the the account is available. Once you lost access to your workspace account it's too late. I'd download a copy of all messages on the server to your Local Folders account. You'd have to manually re-create any folder structure you may have underneath Local Folders. Download messages for each folder in smaller batches, not everything at once. Email servers don't like mass transactions, and may limit the amount of data you are allowed to transfer within a certain time frame. Depending on the size of your email archive this may be a somewhat tedious process, and it won't be in one step either. Once you got a local copy of all your messages make sure to create a full backup of your Thunderbird profile. https://support.mozilla.org/en-US/kb/profiles-where-thunderbird-stores-user-data#w_backing-up-a-profile Having said that, you should create profile backups regardless on a regular basis. You don't need to download message copies from All Mail, unless there are messages in All Mail which have no other label, i.e. are in no other folder. Alternatively you can download your entire message archive from Gmail outside of Thunderbird. It might be a good idea to do that regardless, just to have another backup. Once you got the new account ready you can create your desired folder structure on the new (IMAP) server, and upload your messages to the new server.