Office365 new user with same username as old deleted user


Weird issue with Office 365.

We setup a new user who is using the same account name as an old user. The old user was deleted a long time ago. When the new user setup their mailbox on a totally different computer the mail from the old user was loaded into the mailbox.

Old user: Bob Smith
Old user account name:

New user: Brian Smith
New user account name:

Bob smith's old mailbox loads into Brian Smiths new mailbox.

This is all on Office 365 with dirsync. The old exchange server has all mailboxes deleted and is currently off.

The old user was deleted a long time ago.
Jonathan RoblesOwnerAsked:
Who is Participating?
Vasil Michev (MVP)Commented:
Seem the mailbox was not deleted, and soft-matched after you created the new user. Dirsync will 'link' users with matching Primary SMTP addresses, as explained here:

My guess is that you (or another admin) had a reason to preserve the old mailbox. If this is no longer valid, you can delete the user and mailbox from O365, then run Dirsync again.
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