Saving or Copying bMail Mail

This procedure is aimed at helping departing staff to save important email in a form that is easily accessible by their colleagues. We recommend copying email to a shared bMail account (aka a special purpose account, SPA). Colleagues can then access the shared account to read mail. While this document will give you the basics, we recommend that you contact acg@eecs for help with the process.

Google has limits on how much mail can be uploaded or downloaded in a day. Downloading via the Takeout service is not subject to these limits, but it can still take more than a day for a large mail store. You can see the size of your email here: If it's more than 1 GB, allow a few days to get it all sorted out. Do not wait until the last minute to transfer your mail!

Exporting your mail from bMail to a local copy

Google provides a service called Takeout for exporting all of your content from its services. To use it, in a browser where you are already logged in to bMail, go to Choose the "Control your content" option. Under "Download your data", choose "CREATE ARCHIVE". If you want to download other information for your personal records or for your colleagues, you can do it here. This procedure will only cover email handling.

Under "Select data to include", choose "Select none." Then find Mail and click next to the gray X. If you want to choose only some mailboxes (labels), click the down-caret next to the green check, then Select labels, then choose the labels you want, and click Done. At the bottom of the page, choose Next.

Choose File type .zip, Archive size (max) 5GB. All of our computers support zip64, so you can ignore the warning. If you are saving a copy for personal use and plan to open it on a computer with Windows XP or earlier, choose a max size of 2GB. Whatever size you choose, if your mail is larger, it will be broken into multiple .zip files. Make sure you download them all when you get to that step.

Choose Send download via email for the delivery method, then click "Create archive". There will be a wait of hours or days before you get the mail letting you know the archive is ready.

If you just want to save the mail in case of emergency, when you download the zip archive(s) you're done. Just put it/them in a safe place. If you want them available to your colleagues, then I recommend uploading them to bDrive on an SPA for your group.

If you want your colleagues to be able to view and work with the mail on a regular basis, proceed to the next section on using Thunderbird to upload mail.

Copying mail up to bMail with Thunderbird

For this procedure, you'll be connecting to a special purpose account (SPA) with Thunderbird, not to anyone's personal account. I tested with the latest Thunderbird 12/2016 and did not need to enable IMAP in bMail (!) nor allow "less secure applications".

Configure Thunderbird for bMail

  • Open Thunderbird
  • If it doesn't immediately ask you to create an account, choose Create a new account, Email in the large pane to the right.
  • Select "use my existing email."
    • Your name: [the group the SPA is for] e.g., Administrative Computing Group
    • Email address: [] (e.g.; this is the SPA name without the spa-)
    • Password: [leave this blank!!]
  • "Continue."
  • "Manual Config."
    • Incoming: IMAP   993   SSL/TLS   Normal Password  
    • Outgoing: SMTP   465   SSL/TLS   Normal Password  
    • Username Incoming: [] (e.g.
    • Username Outgoing: [] (e.g. without spa-)
  • Click "Done" button. You may need to re-test before Done will become active.
  • Change to OAuth2 authentication (you can't choose this when you first set up the account).
    • Select the account on the left and choose "View settings for this account" in the main/right pane.
    • Choose Server Settings on the left and change Authentication to OAuth2 on the right. Make sure the User Name is
    • Choose Outgoing Server (SMTP) on the left, select the server on the right, and choose Edit. Give it a meaningful name, change Authentication to OAuth2, and make sure the User Name is without the "spa-". Say OK.
    • Say OK again to close out of account settings.
  • Choose the account on the left and click on Inbox or choose Read Messages. You should get a pop-up window with the familiar CalNet authentication. Log in as the SPA. You'll be asked to allow Thunderbird to have access to your mail; say yes. You should get the Inbox with any messages that are already in it.

Copy the exported mail up to the bMail SPA

  • In the Thunderbird where you set up the SPA in the previous step, choose "Local Folders" in the left pane and then "View settings for this account" in the right/main pane. Note the "Local directory" location and open that folder in Windows. Quit Thunderbird.
  • Open the zip archive(s) of mail downloaded from Google. Copy the .mbox files into the Local Folders directory. It's probably a good idea to rename them and remove the .mbox, since otherwise it will become part of the folder name. Hang on to the zip archive(s) until you're sure all of the mail has been copied.
  • Start Thunderbird. You should see the mail boxes under "Local Folders" on the left and be able to open them and read mail.
  • You can now drag the new folders up to the SPA account to copy the mail up to that account in bMail. I recommend doing just 2-3 at a time. It takes a long time to copy at the best of times, and bMail/Google has a limit of 500MB a day. This means it could take days to copy all of the mail back up to Google.