Move the messages you want to keep into the Local Folders account in Thunderbird.

If you then want to stop Thunderbird collecting new messages from the Gmail account, just remove that account from Thunderbird.

Thank you! I do want them to still be in the Thunderbird app, as I need to search for emails and use them - I just no longer want them on google's servers, so I don't want to remove the account.

If I move them to the local folder you suggested, will I still be able to search and use them within the TB desktop app?

Moving the messages to the Local Folders account in Thunderbird has two useful outcomes.

• The messages are stored in Thunderbird, independent of Gmail.
• They are removed from the Gmail server.

And being in Thunderbird, they remain accessible and searchable.

Now they are no longer stored within the Gmail account, you can remove it from Thunderbird. And you need to do this or else find some other way of disabling the account so it doesn't continue to collect new incoming messages. Since it is now empty, there's no point in keeping it, and removing it is the simplest way to avoid further download.

http://kb.mozillazine.org/Local_Folders

I really appreciate your patience....I'm new to TB and have tried my best to research this but alas.

If I do want to keep syncing the gmail - how do I go about that without losing the 31,000 emails or having them sync back to gmail? I guess that would be my ideal scenario; I've just not yet been able to make that happen...they start deleting.

I just want the 31,000 local and to add to TB locally, any others I want - but remove them from gmail.

So, If I delete on gmail, will they automatically delete from TB?

Moving to Local Folders will clear them from the Gmail server. Messages in Local Folders are no longer synchronised with the Gmail server.

The whole point of synchronising (which means using IMAP) is that both server and all connected clients see the same set of folders and messages. So you can use computers in different places (work, home) or your phone or tablet and still be able to see all your messages. The key to this is storing those messages on the server so they can be shared to any of your clients or devices. Delete a message in any one of these places and it disappears from all.

If you want to detach messages from this synchronising process and have just one local copy, separated from Gmail, move them to Local Folders.

Why are you deleting messages? Because you don't want them any longer, or because you need to release some disk space?

If you're only using one computer and don't need to see messages on other devices, you may be more comfortable using a POP connection to Gmail. This will simply download each and every message to your computer and remove them from gmail. But that brings us back to why you want to remove them from the Gmail server.

Privacy - I don't want anything on google's servers long term.

Well, you can do any of these:

1. use IMAP and set up a filter to automatically move all incoming messages to Local Folders;
2. use POP and all messages will be downloaded and deleted from the server automatically;
3. simply don't use gmail. There are other providers out there.

But you started out talking about "backup" which puts a distinctly different cant on it; a backup is supplementary, not a replacement.

Great. Thanks for all your help.