Backing up your Gmail account using POP
If you use Gmail, you should want to have a local backup of all your e-mail even if you always use the web interface. This will make sure you have all your precious e-mails even when Google makes a mistake or shuts down your Google Account. It can happen to you.
I’ve been using Gmail since the beginning of the beta, and have over 6GB of data in 250K+ messages. After switching laptops I decided to rebuild my backup by starting from scratch. I did this by disabling POP access to Gmail, and then re-enabling it for all mail ever sent. You can find these settings in the Forwarding and POP/IMAP tab of your Gmail settings.
Next configure your client. Any e-mail client can receive POP traffic. You can set this up using instructions from Google
, from your e-mail client, or both. I happen to use Mail.app on Mac OS X Snow Leopard.
Now for a very important step. Every POP3 client should have a setting that asks you whether or not the messages should be removed from the server after retrieving them using POP.
Your first response will be “No way, I’m keeping my messages on Gmail”. Still, you should tell your client to remove the messages from the server because Google uses this setting for something else entirely.
Your Gmail will not be deleted. Google treats the delete requests your POP client sends to configure the batches of messages that your client can retrieve. If you have a lot of e-mail, and do not allow your client to “delete from server”, you will not be able to back up all of your e-mail.
Some clients, including Mail.app, have other settings for “delete from server” besides yes and no. For example “delete after a week” is the default setting for Mail.app. Do not use this, allow your client to send the delete signal to Google’s servers immediately. If not, your mail retrieval will stall at some point (for me it was after about 216,000 messages).
Now let your client do its work and slowly but surely you will have a nice, local copy of all your Gmail. Which you should back up to an external disk or a cloud server, but that’s another story.
Thanks to all the contributors to my question on the Gmail Help Forum