Remove delegated account after license is removed (Outlook)

[bschmiedelertempconnet]

There is a user who has access to a Mailbox in O365 which no longer has an active license. I tried to remove the account from his Outlook for Windows by following these steps. 

https://businesstechplanet.com/how-to-remove-a-delegate-in-outlook-365/

When I checked the user who no longer has an active license does not have any delegated permissions. 

But the user to whom he delegated permissions still sees the mailbox in their outlook, and we cannot remove the mailbox. When I try to remove it by going to File ==> Account Settings ==> Account Settings and looking for accounts to remove, there are no accounts to remove.

Googling this issue I have found suggestions to turn off auto-mapping, as this sometimes fixes the issue (see here). A little reluctant to do this, as I am not very experienced in Powershell. 

What is the correct way to overcome this issue?

Thanks,

Bryan

[#2]

If you're not seeing the mailbox listed under Account settings, automapping is the likely culprit. Though in this case you can simply remove the Full access permission, which is also doable via the admin UI.

[#3]

Vasil,
I appreciate the reply. But I think I should clarify.

User A is seeing user B's mailbox in their outlook. When I try to remove it from the Outlook GUI I do not see that mailbox listed.

When I go to user B's account in Active Users in Exchange Admin Center and look there are no entries for mailbox permissions, i.e. that user has not delegated anything.

So why is user A's outlook still showing the user's account in their Outlook?

[#4]

Might be an orphaned permission entry. If you don't see any permissions in the admin UI, I'm afraid PowerShell is your only option, as you will have to clear the stale info as per the article above.

[#5]

Really would rather not perform brain surgery on this user's account (read: Executive). Would resetting the profile fix this?