Shared mailboxes

Copper Contributor

I got two shared mailboxes in an Office 365 enviroment, let's name them 'Mailbox A' and 'Mailbox B'. These were resource mailboxes in the past, which were migrated from an on-premise Exchange server.


They were used by five users until recently. Now they're only used by 2 users, one of them is a user that got access to the mailboxes just recently.


There are 2 problems now:

1) The user that got access recently to the shared mailboxes, frequently get the error: 'Cannot expand the folder' when trying to open the mailbox. 

2) The shared mailboxes still are visible for the users that don't have access to it, but they can't open it. When trying, they will get the same error as the user in problem 1.


I checked delegations and permissions for the shared mailboxes, they are all right. Only the two users that should've access to it are set in there. 

Besides that, I changed the resource mailboxes in shared mailboxes through Powershell, but this doesn't seem to make an difference.


For problem 2, even when setting up outlook fresh with a new profile, will automaticly add those shared mailboxes, which they don't have access to anymore.


Now I would like to know how to solve these two problems. I've searched a lot, but don't seem to be able to find anything that would help me with that.

6 Replies

@ChristianBergstromI guess you're referring to this for problem 2?
I tried that just now, but since those users don't have have any access to the mailboxes, it won't let me disable automapping for those users.



WARNING: Can't remove the access control entry on the object "CN=mailbox,,OU=Microsoft Exchange Hosted Organizations,DC=EURPR08A002,DC=PROD,DC=OUTLOOK,DC=COM" for account
"EURPR08A002\***************" because the ACE doesn't exist on the object.

@Alexander Bontenbal Yes. Quite funny as I am just about to leave the computer again...! Try adding the users again, then remove.

@ChristianBergstromHehe, bad timing each time... Looks like it works now :) Now I only need a solutions for problem #1

@Alexander Bontenbal Great! When and how does nr 1 occur? (some more details please).

It's used on a Windows PC with Outlook, PC runs 24/7 usually, Outlooks stays open as well.
After some inactive time, like an hour or more, the user can't open the shared mailbox in Outlook anymore. If the user restarts Outlook, than it will work again, but understandable it's annoys the user each time he has to restart Outlook just to access the shared mailbox.

Now I already tried with a new Outlook profile, reinstalling Outlook and manually added the shared mailbox to Outlook, but the problem is still recurring.