Forum Discussion

Copper Contributor

Sep 05, 2019

Solved

Adding Domain to Existing O365

My company recently acquired another company with about 60 users. We use Exchange Online for our email with an on premise AD and run a DirSync setup. The smaller company currently uses O365 for m...

office 365

HidMov
Sep 05, 2019
Hi dalbright

As far as I'm aware, there isn't a easy native way to join to different tenants together, though as more businesses sign up to EOL and this becomes more common, I'd hope that MS introduces a mechanism to do this (as well as splitting up a tenant).

The only thing I have in my notes is a document from on how to do this manually

https://docs.microsoft.com/en-us/Exchange/mailbox-migration/migrate-mailboxes-across-tenants?redirectSourcePath=%252fen-us%252farticle%252fHow-to-migrate-mailboxes-from-one-Office-365-tenant-to-another-65af7d77-3e79-44d4-9173-04fd991358b7

I've not done this myself - we were looking into it as a client had the same requirements as you, though in the end they decided to keep the tenant separate.

HidMov

Iron Contributor

Sep 05, 2019

Hi dalbright

As far as I'm aware, there isn't a easy native way to join to different tenants together, though as more businesses sign up to EOL and this becomes more common, I'd hope that MS introduces a mechanism to do this (as well as splitting up a tenant).

The only thing I have in my notes is a document from on how to do this manually

https://docs.microsoft.com/en-us/Exchange/mailbox-migration/migrate-mailboxes-across-tenants?redirectSourcePath=%252fen-us%252farticle%252fHow-to-migrate-mailboxes-from-one-Office-365-tenant-to-another-65af7d77-3e79-44d4-9173-04fd991358b7

I've not done this myself - we were looking into it as a client had the same requirements as you, though in the end they decided to keep the tenant separate.

VasilMichev
MVP
Sep 06, 2019
Agree with the above, there's nothing useful that Microsoft currently offers in that area. There are however some third-party products that can automate the whole process, of course at a price. Look them up if you are interested.