After a while you have a long list of attached mailboxes that you don't need anymore.
And sometimes those mailboxes won't disconnect properly.
How do you get rid of them when the mailboxes are still listed in your folder panel though the mailbox but not listed in Account Settings/Change/More settings/Advanced?
You can view the following attribute in ADUC:
Search for the (shared) mailbox you want to remove, right-click the (shared) mailbox, in the Attribute Editor, double click the msExchDelegateListLink attribute, check if your account is listed there. You can remove your account from the msExchDelegateListLink attribute to clear Automapping.
Restart Outlook and check if the shared mailbox is removed.