So I recently ran into an issue where I had a user who’s Local AD account had been deleted but their Office 365 Mailbox was still showing up. We tried to bring the user account back, however the AD recycle bin was not enabled. So we had to create a brand new account for the user and then work from there.
We originally planned to create a new mailbox and let the user start from scratch. However we ran into an issue were the old mailbox would not go away, and it was preventing us from migrating a new mailbox into Exchange Online for the user.
I then found the following Exchange Management Shell command which will allow you to connect the local AD account to the Exchange Online Mailbox.
Enable-RemoteMailbox USERNAME -RemoteRoutingAddress [email protected]
After running the command the user is now able to log in with their new AD account and have access to their mailbox.
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