Sunday 5 December 2021

Restoring from Gmail Backup

 Migrating to a new Gmail email account is a lot easier using Google Takeout this Thurderbird Add-on ImportExportTools NG. I have been splitting up my email accounts so that I have several distinct accounts - more on that below. The gist was that in the past I was forwarding all mail into one account which I'm no longer doing but now I want to move all that old mail, ~30,000 emails, into a different mailbox. Recommendations online were to connect Thunderbird to the two accounts and move messages in batches but in practice Gmail times out these connections very quickly and the batches are way too small. Instead I ended up exporting my email and importing it - why Google does not offer an import of the format in which they export boggles the mind, and while it's possible I've simply missed proper screen where this can be done, somehow I think not. This seems to be one of those things that is easy enough, but not obvious and took a bit of searching. 

The easiest process I found was to use the ImportExportTools Add-on:

  1. Spring cleaning time of your old email! Newsletters and automated notifications that were being filtered to a folder go 💥, gone.
  2. Go to Google Takeout and export mail. This produces a ZIP file which you can extract and there is a single large MBOX format file
  3. Install  Thurderbird and the ImportExportTools NG add-on
  4. Import the MBOX as a local folder with ImportExportTools
  5. Re-Export the email from local folder to a directory of EML files with ImportExportTools
  6. Connect Thunderbird to your new email account
  7. Import with ImportExportTools "all messages from a directory" and import into your "All Mail" folder
  8. Wait.  ... Wait ... Ponder if you should have done more aggressive cleaning... And wait. My mailbox I think it ran at least 3 hours? Not sure, but a lot time, many hours.
  9. Tada! Go into your Gmail account and try a few searches and see if you got everything you expected.
This ImportExportTools is generic enough you could use it for any sort of mail service and I think I could have done the initial export with it instead of Google Takeout thus saving a couple steps. My confidence isn't that high that 100% of the email was coming across with the connection timeouts so I would kind of suggest sticking with Google Takeout to get the mail and go through the extra steps and also having the Takeout as a backup is a good idea regardless.

Really this stemmed from wanting to split from One Mailbox To Rule Them All, which I already was moving away from. I'm working with 4 mailboxes now.

A personal email address which I really only use with other people; friends, family,  like actual humans. Mostly, a couple exceptions but so few as to be trivial. This is on domain and I have a handful of aliases (yay for grand-fathered free Google Apps account).

A general email address I use for most everything - online services, loyalty points programs, emailing with contractors, the bank, etc. Some people call this a "personal assistant" in that it's handling everything outside your most personal emails. A lot of my other mailboxes forward into this one. This is where I wanted to move all the mail.

A junk email address particularly to get to websites where they require an email or registration to access whatever specific thing that I need and is probably a one-off and I really don't want to hear from them again. Basically any email into this mailbox, I flag the sender as Spam so it stays pretty clean but it is functional enough to pass a registration. Some people like using 10 Minute Mail or similar.

A second "personal assistant" email address but for the household. My wife and I sign up for Spotify - goes on the household mailbox. Also, fun spy-craft tip: you can use this as a secret message drop by writing a DRAFT email which is then read by the other person and then deleted. This way the message never went through all the delivery servers so there's no logs of it and there won't be multiple copies of it.



  1. ImportExport seems to have some issue that when the message is imported, it's date is the date of the import. It's a bit odd because it looks fine in Thunderbird (IMAP) but then from Gmail App all the imported messages have the same date.

  2. Post title changed to reflect that really this method is more suitable for restoring from backups. I haven't really found any good info about the date stamp thing. I may keep looking but it's not ideal.


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