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Hi,
I'm syncing an AD On premise user identity to Azure AD using Azure AD Connect.
For initial information, this AD On premise user has an Exchange On premise mailbox.
My problem is that when I sync an AD On premise user to Azure AD, then I give a Business Basic license to the synced user. Information appears that "This user's on-premises mailbox hasn't migrated to Exchange Online, the Exchange Online mailbox will be available after migration is completed."
How to keep a synchronized user's Exchange Online mailbox active without migration?
Actually I don't need Exchange Onprem mailbox because I want to use Exchange Online.
If so, you could disable Exchange on-premises mailbox directly (Disable mailbox from Exchange on-premises admin center). It will disconnect Exchange on-premises mailbox from AD account.
Then run "Start-ADSyncSyncCycle -PolicyType Delta" to force update AAD Connect. After that you will coudl assign license to this account from Microsoft 365 admin center.
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Ok, this means that this is the only way to make Exchange Online mailboxes active without migrating On premise mailboxes.
That's the expected behavior, thanks to AAD Connect Exchange Online "knows" that an on-premises mailbox exists and will not provision a cloud mailbox (as having a mailbox both on-premises and in the cloud for the same user is not a supported scenario). AAD Connect does not synchronize mailbox content, this is why you need a proper migration tool on top of AAD Connect if you want the mailbox data to be available in Exchange Online too.
Hi Michev,
But if in this case I don't want to migrate mailboxes from Exchange On premise and only want to sync the Identity, what should I do to make the Exchange Online mailboxes active?
Maybe I can desync certain Exchange On premise attribute on Identity user AD On premise to be synced, or something like that?
Thank you,
Let's ask it this way, why do you need to have an Exchange Online mailbox, if the user already has a mailbox in your on-premises Exchange system? Having two mailboxes for the same user is not a supported scenario and can potentially cause issues with mail delivery and such.
Yes, you can change the AAD Connect config to not sync the relevant Exchange properties, but again, why do you need to have two mailboxes?
Actually I don't need Exchange Onprem mailbox because I want to use Exchange Online.
I just want to sync the Identity so that the Identity user can be managed from AD Onprem.
Regarding the exclude Exchange properties, how do I prevent the synced Identity from reading the Exchange Onprem mailbox on the Identity user so that the Exchange Online Identity User can be active without the need for migration? And what properties do I need to exclude?
In that case, you don't need to do anything other than enabling Dirsync in its default configuration. The user's identity will be synced with Azure AD, and you will be able to manage him from on-premises regardless of where his mailbox resides. Ignore that warning message, it only applies to mailbox content, not the user object and its properties.
You don't need to license the user for Exchange Online either, but if you are assigning a "bundle" license it doesn't matter anyway.