Office 365 and exchange 2010 mailbox issue

we are in a hybrid mode. a large number of users are still on premise (exchange 2010) while a few are in office 365

A few users had secondary mailboxes that they could open when they were on premise. These mailboxes were never removed from their outlook account prior to being migrated.

The users have been migrated the mailboxes they used to access are not

Problem

Outlook 2013 user in office 365 has mailbox access to on premise mailboxes. They can access the mailbox from within their mail box.

We want to remove those additional mailboxes since cache mode is turned on for office 365 users.

I tried removed it from outlook but it tells me to go into account settings and remove the mailbox. Outlook 2013 does not show any additional mailboxes in account settings. How can I remove these additional mailboxes?
iamuserAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Vasil Michev (MVP)Commented:
Seems those were auto-mapped, so just remove the permissions via Remove-MailboxPermission or via the GUI. Or via ADSIEdit/attribute editor, the msExchDelegateListBL attribute.
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
iamuserAuthor Commented:
I did remove the user's permissions to the on premise mailbox via GUI/EMS but the mailboxes in question still shows up in outlook 2013. User just can't open the mailbox which isn't what we want either.  We want to It remove the mailbox from showing up.
0
Vasil Michev (MVP)Commented:
Check the attributes, the GUI/cmdlet can fail in some cases, leaving the actual attributes in place. Another way to confirm it is to get the autodiscover.xml response for that user, the delegate will be listed on the bottom.
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Office 365

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.