Migrating to Gmail with Thunderbird

[Phasma Felis]

My current primary email address is a POP account that I check with Thunderbird. I'd like to migrate to using my Gmail account as the primary, to benefit from cloud backups and Gmail's excellent web client.

The caveats are:

• I've got about 2.5GB of mail stretching back about 15 years that I want to migrate.
• I want to keep using Thunderbird as my main client (I don't trust the cloud quite that much, and I like to read saved mail on the bus sometimes).
• I've got a couple of secondary accounts that I'd like to forward to/be checkable from Gmail, but if I hit Reply To, I want it to send from the account it was received in, by default.
• My Thunderbird account has a couple of dozen different folders with fairly sophisticated filters determining what goes where.

Any obvious pitfalls? It should all be doable, but I already ran into some pain when I tried this last year. (Thunderbird spent 3 hours uploading mail, hit one message with an attachment >10MB, and aborted the entire operation with an unhelpful error message. Think I've dealt with that, at least.) So if you've tried this before, I'd love to hear what issues you ran into.

[yewbie]

I know this isn't really helpful but I tried to do this a few years back (probably like 10), and ran into so much trouble that I picked out a few hundred important emails, manually forwarded them over and deleted the rest.

Good luck to you, I know if you can't get the automated systems build into thunderbird and gmail to work there is a linux program specifically made to do these transfers and I have used it to move stuff from a exchange 5.5 system to a more modern system even with large attachments.
http://freshmeat.net/projects/imapsync/