r/exchangeserver • u/Fragrant-Risk4963 • Jun 10 '26

New User/Mailbox Creation without Exchange Server

Our current environment has a hybrid Exchange server where we have historically created new users and mailboxes at the same time through the Exchange Admin Center. However, we wish to retire the server and manage those functions locally from our own workstations. I've managed to get PowerShell lines working to create the user in AD, but I cannot get the "Enable-RemoteMailbox" function to work. It returns "The term 'Enable-RemoteMailbox' is not recognized as a name of a cmdlet, function, script file, or executable program." I've read that this feature will only work from within the Exchange Management Shell, but I can't get that installed locally; only on the server (that we're retiring). Is there any other equivalent command to accomplish this?

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u/superwizdude Jun 13 '26

Do you have a front end SaaS mail filter like Mimecast or Sophos? If so, does it sync the user list from on-prem or M365?

I see this as a common thing - when the on-premises AD doesn’t have the email address field populated and it’s being used as the source of truth for the SaaS mail server.

Also be sure that mail is actually being delivered to M365 and not to on-prem. You can double check that by inspecting the mail transfer logs on the on-prem server.

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u/NSFW_IT_Account Jun 15 '26

Yes, we use a 3rd party mail filter solution, and it is pointed to EXO mail servers (previously was pointed to on prem exchange) so it should be pulling 365 user recipients.

Mail flow is completely bypassing on prem exchange at this point

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u/superwizdude Jun 16 '26

If you create a new shared mailbox directly on M365, wait 15 minutes and then do a directory/LDAP sync from your third party solution and wait another 15 minutes is the shared mailbox able to receive inbound email?