Thunderbird will not be able to log in to Gmail anymore and the files you have will still exist in your computer.

Be sure to check and uncheck some options (I don't have the exact ones) that tell TB to keep copies of everything.

Go to Tools->Account Settings, then to your account and Synchronization and Storage. Be sure to have Keep message for this account on this computer on and Synchronize all messages locally regardless of age and Don't delete any messages

Also click the Advanced button and ensure all folder are synced.

Then, regularly backup your TB folder in C:\Users\YourName\AppData\Roaming\

Make a full backup of the Thunderbird folder there as regularly as you like.

That's great, I think I'm pretty well set up now for damage limitation should anything happen :)

Agree with iampowerslave regularly backup your TB folder in C:\Users\YourName\AppData\Roaming\

I would not put all eggs in one basket without making regular backups or downloading copies and keeping them in 'Local folders' mail account.

I have heard of people losing emails in IMAP and POP accounts due to various reasons. If your computer crashed whilst Thunderbird was synchronising, the computer could have lost files and synchronised any empty file, so loosing data on server. If an AV program located a bad email, it could do a repair fix on the entire file messing it up, which if synchronised to server could cause issues. The list goes on, but the bottom line is no matter whether you use POP or IMAP back up Thunderbird Profile on a regular basis if emails are important.

Thanks again. I was previously backing up my pop emails to Sugarsync, but what would happen I think is that every time I'd get a new email. the file folder in app data would be updated, and some folders were about 2gb, so Sugarsync would then need to restart the syncing on this file and what actually happened is that my system got corrupt and I lost a load of emails and I tried to get them back from Sugarsync, but because of this problem, it was months since the last proper backup of the most important (biggest) account folders.

This was a reason I pushed to IMAP so at least if I get a local corruption, I'll always have the mail stored on the server too, whereas before, it was all just loca via pop.

IMAP is a Synchronized stuff so if just by chance you DELETE every folder in TB and it tells the Server to do the same, your e-mails will get lost from both ends.

Do you get that picture?

That is why having a zipped folder is safer. And the only way it will be safe is if you back it up to an external drive that you store at some other place than your home or office so in case of the worst scenario (fire?) you'll always have a copy of everything.

Yep that's the ultimate way for sure :) I guess if mails were saved as individual files and not as part of a bigger INBOX file or folder file, then the syncing to a cloud backup wouldn't be a problem, but because it's syncing the 2GB files, and any time a new mail comes in, the file structure changes, it wants to sync from the start again, so never fully syncs on a folder that has regular activity.

I'm hoping the likelihood of deleting folders by mistake and then the change being reflected on the server and me not being able to recover any of the deleted files is realllyy reallyy low :)

I agree partly as I develop software and have set a simple Folder/File structure but then you'll have to work with files with IDs and will have thousands of them and the file system will suffer and you'll sync will suffer too. It is not that easy, or at least it wasn't when this software was born.

I have a huge DB (8GB compressed with 7zip) and it always behaved nicely. Think about those poor Outlook users with 1 (one) PST file that has everything in it.

I do order stuff in folders so I don't have extremely large files either and only the inbox changes permanently the rest of the folders are mostly static and could be easily synced once.

Thanks again for the input. When you you zip it, you mean you just compress the Thunderbird folder in app data > roaming so it takes up less space on your external?

Similar here, I've a few accounts on TB with a collective folder size of about 9GB, some folders on some accounts hold a lot more than others though.

Anyway, with IMAP, locally stored fetchings and (I'll try to do) regular external drive back ups, I don't think there's much else I can do. Just a pity there's no way to do it better with cloud back ups so it does it all itself without thinking :)

Yes, by Zipping I mean that. Having a full backup of all TB accounts and its data.

IMAP is already cloud storage. But just as you thought, if one day Gmail goes crazy or your government decides to kill it for your country, you can have a backup.

Haha, hopefully that never happens :)

Would be nice to have the whole folder synced to the cloud too though, then all my settings and add ons, extensions etc would be saved too :)

Maybe there's a way to periodically take a copy of the folder and back up the entire thing to the cloud automatically so at least every 2 weeks or so there's a fresh copy and all you'll ever lose will be 2 weeks of emails in the event of a catastrophe :D

Of course, you can "script" that with basic tools or you can have backup software do that for you. There are plenty of options and there are backup tools with "Data Deduplication" options that will detect the part of the file that changed and only backup that difference instead of backing up the whole file. Saving time and space (it takes a bit longer to identify what has changed)

Plus, if you do not compact folder often, the email messages are just appended one behind the other, and the deleted ones aren't removed from the big file (folder) so the file only changes adding new e-mails to the bottom.

Thanks again for the info. I'll be looking for a cloud backup provider who can offer data deduplication so, never knew what that was called :)