How do I migrate old mails from PST file or public folder into a Group?

Brass Contributor

I have to migrate several old projects into (new) Office Groups. One of the tasks is to 'import' (lots of) old mails for reference. Sometimes I have old (and shared) PST files as source. In other cases the mails are stored in old public folders. 


It seems not to be that easy. Can Powershell be a solution? I appreciate any hint. 

15 Replies
You can't sounds to extreme to me :-)...I would say there is nothing in the box for your scenario and problably third party tools won't help here understanding is that the Microsoft Gaph should be the medium to do this migration, but I don't have an idea about how to do it

Juan, if I understand well, Robert wants to import (lots of) old mails into the mailboxes associated with Groups.

As we have discussed in the thread I referenced, this is not supported at the moment.

Apart from forwarding every single mail to the Group email address, the only workaround appears to be to leverage an unsupported "hole" in the system and do a lot of drag and drop by means of OWA, which, I think, is a little troublesome.

Since this is a very frequently requested feature, I really hope that one day you can come out with one of your scripts to solve the problem. ;)

But, in the meanwhile, IMO the answer to Robert is: "you can't".

"workaround appears to be to leverage an unsupported "hole" in the system and do a lot of drag and drop by means of OWA"


What do you mean? Is there a unsupported way?



Oh, thanks. But this sounds not good. No import and obviously no export functions. Is Sharepoint a dead end for mail?

Yes. The unsupported and undocumented workaround is described in the thread I referenced above.

Basically you add the Group mailbox as a shared mailbox in OWA and then you can drag and drop mails from other folders to the Group mailbox.

There are several threads discussing this issue. The problem stems from the fact that the shared mailbox that is connected to a Group behind the scenes is not surfaced as a standard mailbox, but it is rather used in order to implement a "conversation space" for the Group.

Hence currently there is neither an import and nor an export procedure.

Haven't personally tested it (yet), but QuadroTech's ADAM should support ingestion of PF items to O365 Groups:

Yes, good find!

Not sure, though, that it can migrate also emails to Groups conversations...

Is that written clearly somewhere in the documentation?

Any feedback on the raised question from Salvatore until now or any other good way of solving the root issue?

Yup, the tool can migrate to Groups as well. Best contact them to get a demo or something.

Hot off the presses:
Use batch migration to migrate Exchange 2010 public folders to Office 365 Groups


Cheers, Brad. Do you (or anyone else) know whether this will work for migrating a O365 user's mailbox to the O365 group?


A year later and still no migration tools for site mailboxes, kind of associated with this. One can export to PST and wasn't it possible to import PST into public folder. Could then use public folder -> group migration or is that route blocked for Exchange online?

Amazing at lack of migration tools within Microsoft's own software suite. I can't believe it's not possible to write a program to read a PST and write to Office 365 group conversation. Yes, I appreciate the threading will probably be lost but we can put up with that. To be honest, most users hate group conversation mode compared to how Outlook/Public folders did it.