Multiple users coming up in Outlook from Office 365

Tarkisal used Ask the Experts™
I am the system admin for my company. I should have full access to all e-mail mailboxes in my organization. All of a sudden the names of many (but not all) of my users are showing up in my Outlook 2016 mailbox with all of their mailboxes (Including inboxes, deleted items, any folders they have made, etc). What's strange is on the web version of my mailbox these names are not shown, nor on my Android app. The extra mailboxes only show up in my Outlook 2016.

From the research I've done it should show multiple users in my E-mail Account settings. However, I only see mine (screenshot 2.) I don't know where these extra mailboxes are coming from and when I try to close or delete them it says "The group or folders is associated with an e-mail account. To Remove the account, click the File Tab, and on the info tab, click Account Settings. Select the e-mail account and then click remove." But again, I only see my account there.

This is making my Outlook unsable since it's trying to sync with 25+ mailboxes!

More info:

-Outlook 2016
-Office 365 sync
-Started today
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Ahem, is there any particular reason to have full access on all these mailboxes? Having admin access doesnt usually mean you can snoop around in other persons's mailboxes.

Anyway, this happens because you have added the Full Access permissions via the GUI, which in turns uses the Automapping feature, thus causing all mailboxes to pop up in your Outlook. Go to the EAC, remove the permissions and re-add them via PowerShell instead. The cmdlet you have to use is:

Add-MailboxPermission -User -AccessRights FullAccess -AutoMapping $false

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The last part will make sure they will not pop up in Outlook, but you will still be able to open them on demand.


Thank you for your prompt response - that's exactly what I was looking for.

(And unfortunately I am tasked to do audits so I have to have access to each mailbox. Trust me, I'd rather not.

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