Migrating email from Office365 to Gmail Workspace as cleanly as possible

May 10, 2023 3:35 AM

It's been a few years since I've done this, (and never from office365). Previously when importing to gmail, I used IMAP and manually dragged and dropped emails from one account to the other. I like the thought of not having to nurse an IMAP client all day... Gmail is giving me the option to 'migrate' emails (I think from the inbox only) using POP. But I'm

wary of POP because:
- I don't want the emails on office365 to be changed at all
- Ideally I'd want to move sent items too
- I'm not sure what the 'start date' will be for which POP emails will be imported. Probably not an issue, it'll probably pull them all over, but I'm still leery.

Any tips on this process? Loads of the articles on this topic are basically ads for some dodgy sounding tool to do the job for me, which I'm EXTREMELY leery of!

The best result is all of the emails which are currently in office365 ALSO sitting in Gmail, copied, not moved. Sent items too.

At the moment I'm thinking manual IMAP, if Google still allows it but happier with a more straightforward option, obviously.

posted by dance to Computers & Internet (8 answers total)

I'd start here.
posted by flabdablet at 4:41 AM on May 10, 2023

If you have one of the following Workspace editions: Business Standard and Business Plus; Enterprise; Education Standard and Education Plus; G Suite Business. You can use their data migration service.

If you're running more solo then that and can deal with it on a per user basis, use their Google Workspace Migration for Microsoft Exchange tool
posted by Static Vagabond at 6:46 AM on May 10, 2023

I think I would try the free Mailstore Home for this. It archives email from many systems, and can restore the mail to different systems. I, for example, used it to migrate from Outlook to Thunderbird, and then back to Outlook. It provides a fast search of the archive too.
posted by TimHare at 7:52 AM on May 10, 2023

I would avoid Google’s Mail migrate functionality. Last time I tried it, it silently deleted a bunch of emails, marked a load as spam and set every email to unread.

I ended up using Thunderbird instead. I simply connected both accounts to Thunderbird and then dragged and dropped emails from one account to the other.

If you’re migrating to gmail then copy into the “inbox” and ignore the “all mail” folder, otherwise you’ll end up with duplicates.
posted by mr_silver at 11:06 AM on May 10, 2023

Response by poster: Thanks all

Both of these options looked really promising.

@flabdablet, that was EXACTLY the sort of powerful and genuine looking tool I was after...unfortunately BT Business (who are the subscriber to Office365) don't support IMAP, only POP.

So then I was overjoyed when I saw what @Static Vagabond had recommended, and indeed this SO nearly worked, but sadly my office365 account doesn't have permission to allow use of the tool....

and then I saw @Mr_silver's comment and that actually may turn out to be a blessing in disguise!

Bizarrely and annoyingly the ONLY protocol this office365 seems to support is POP.

I'm really worried it's going to start deleting emails at the source once they're 'downloaded' via POP.
posted by dance at 11:11 AM on May 10, 2023

I'm really worried it's going to start deleting emails at the source once they're 'downloaded' via POP.

Good news, that setting is usually controlled by the mail client.

So when you connect your POP account to Thunderbird make sure that “leave messages on the server” is enabled. (source)
posted by mr_silver at 11:25 AM on May 10, 2023

unfortunately BT Business (who are the subscriber to Office365) don't support IMAP, only POP.

That's not what their help page says.
posted by flabdablet at 11:49 AM on May 10, 2023

Response by poster: I know, flabdablet, I know. And that page cost me a day's wasted industry. But it's wrong - BT's wrong.

Anyway I come bearing good tidings. What FINALLY did the trick was an extension for Thunderbird called OWL. This works. It's not perfect because Thunderbird+Owl sometimes stop at random uploading to Gmail via IMAP (I don't think I'm hitting the transfer limits) and I have to restart Thunderbird to get it going again. There's no error (even in activity monitor) when this happens, it just goes silent on me mid-transfer.

Thanks for all your help
posted by dance at 2:48 PM on May 11, 2023