How to migrate Gmail to another Provider without Breaking the Mail History

This is a practical how-to on moving email from Gmail to another provider.

The main challenge is Gmail’s label system: one email can have multiple labels and all mails also appear in “All Mail”. Most other providers use folders instead, where an email can only exist in one place. If you migrate without taking this into account, you will most likely end up with duplicated mails or a messy folder structure.

In this guide, I document how to prepare a Gmail account so that labels behave like folders, and how to safely copy all emails to a new provider using standard IMAP tools – without losing mails and (hopefully) without unpleasant surprises afterwards.

Have your own Domain!

Quick interrupt! If you don’t have an own domain already, GET ONE. You’re never bound to any provider again and you will never have the hazzle again to change your eMailaddress again if you ever have to move again. At Strato for example, it’s just 1€/month. But there are quite some providers out there.

So get your Domain up and running, and when it’s all fine, proceed.

Okay, back to moving the mails …

The Problem

My main concern was the label system from Gmail. In Gmail, one email can have multiple labels. Plus all mails appear in the “all mails” label. Other mail systems organise emails in folders, and one email can only exist in one folder.

This means that if an eMail is assigned two labels, it will end up as a copy in both folders! Keep that in mind.

Solution 1 (easy but risky!): MOVE

probably the easiest solution would be to simply move the Mails from GMail to the new provider (see below, how). Just

• move one “folder” / label after the other (including inbox) from GMail to your new provider. Don’t forget the “Sent" folder.
• clear the spam and trash folder
• move all remaining mails from “all mails” into an archive folder to your new provider
• GMail should now be empty
• forward newly incoming mails to your new provider.
• DONE

BUT: I didn’t want to move my mails. If something would go wrong somewhere in between, I would have my mails scattered between two accounts. So I wanted to copy all mails and thus have a backup.

Solution 2 (bit more effort): Copy

In my case, I mainly used labels as folders. So every mail SHOULD have just one label. So at least the problem is smaller. But if I copy mails from one folder after the other, how do I recognise mails that I hadn’t put in a folder but just “archived”? After copying all folders, I couldn’t distinguish the mails in “all mails” from mails being in folders. Bad.

My only idea was to have EVERY email assigned a label and have an explicit “archive” label. So we just need to find the mails not having a label.

• empty trash and spam folders (could also be excluded in filter, but hey, maybe just get rid of it)
• create an “archive” label
• search for “-label:inbox -label:sent -has:userlabels” (or if you want to be super safe: “in:all -in:inbox -in:sent -in:drafts -in:spam -in:trash -has:userlabels“). This should list all mails that are currently only archived (i.e. not in Inbox or any user-defined folder). The “-has:userlabels” should ignore mails that are put in folders.
• move all those mails to “archive“.
• First step done! All mails should now be in “proper” folders/labels.
• now copy (not move!) one folder after the other from Gmail to your new provider. Don’t forget the “Sent" folder.
• GMail and your new provider should now have the same mails.
• forward newly incoming mails to your new provider.
• DONE

How to copy / move so many Mails

As I said, I have a bit of a history (close to 10.000 mails) to transfer. If your new provider has an importer, that’s cool. Mine hasn’t and I didn’t quickly find a tool that worked so easy out of the box that I wanted to trust it.

In the end, I

• installed Thunderbird and added the GMail-Account as well as the mail account from the new provider (both as IMAP).
• copied one folder after the other
• validated each folder after copying
• donated to Thunderbird, as it just saved me a lot of hassle.

And don’t forget to

• redirect all incoming mails to your new address
• use your new address
• whenever you encounter an email coming to your GMail address, you might want to change it to your new address. A filter on your new provider can help by putting all Gmail-mails into a separate folder or flags it somehow.

Congratulations! You’re done. And don’t forget your contacts and calendar afterwards as well.

I know it might really sound like a hassle. But at least you don’t need to figure everything out yourself, and afterwards, and the hassle with the labels will never bother again.