Download all mail messages from Gmail including Sent folder items

You can setup an email client to download the entire contents of the account including sent mails if you configure IMAP access. The following settings work for me in Thunderbird although you can probably use any standard email client that you prefer.

Server: imap.googlemail.com or imap.gmail.com
Port: 993
Security: SSL/TLS
Authentication: Normal Password

Once you have downloaded the contents of the inbox you can then save and backup the contents of that mailbox by using the appropriate feature in the email client.

You will also want to check Settings->Labels and ensure all labels have "Show in IMAP" selected (by default, Chats are not).

Good luck to you and sorry for your loss.

I'm very sorry to hear about your wife.

I just wanted to add, you might want to download other data other than Gmail, if she used other Google services. See the "Google Takeout" project here:

https://www.google.com/takeout/

MakeUseOf just happened to post a tutorial on Google Takeout and IMAP backups recently.

First, my condolences.

As everyone has (correctly) said, you want to use IMAP.

For backup, I'd personally use a non-GUI email client though. This will make it easier to backup. And with IMAP, you can still use other clients, like Thunderbird, if you want them to be easier to read.

If I was in your situation, I'd use Fetchmail on Cygwin. Luckily enough, there is already written a tutorial for this at Lifehacker.

Use IMAP4, it will allow browsing messages directly on the server, as well as copying them out. Practically any desktop IMAP client will allow you to mark all messages and drag them into a local folder, or into your IMAP mailbox. (At various occassions I've tested Thunderbird, Evolution, mutt, Windows [Live] Mail, Outlook, Eudora, and Outlook Express.)

Batch downloads can be done using getmail or OfflineIMAP, on Linux or OS X.

(By the way, the custom POP3 server used by Gmail does, in fact, include sent messages, although it has other limits.)