By Ace Fekay
Published 5/11/2017
Revamped 3/31/2018 – Added the option to selectively remove BLs without removing FullAccess permissions to the shared mailbox

Scope

How to remove a shared mailbox that keeps showing up in your Outlook profile that you’ve been removed as a delegate.

This shows how to remove the mailbox permissions and to re-add, and I just added how to simply just remove the backlinks WITHOUT removing FullAccess permissions. The users in this case, must re-add the mailbox in Outlook once it disappears from their profile.

Automapping

Automapping is an Autodiscover feature that was added to Exchange 2010 SP1 and newer, that allows Outlook to automatically add a delegated mailbox without additional tasks.

Autodiscover looks at the mailbox owner’s AD account for an attribute called the MSExchDelegateListLink attribute.

When you use the EAC or PowerShell to delegate permissions to a shared mailbox or to another user, Exchange will automatically set the Automapping feature to $True. In PowerShell you can disable this, but not in the EAC.

This feature populates the MSExchDelegateListLink attribute on the shared or delegated mailbox with the user accounts that will be Automapped, and vice-versa, it also populates the MSExchDelegateLinkListBL attribute on the user account. I look at this as the “back link” to the shared mailbox.

These two attributes are one of nine (9) links and backlinks that exist. Here’s a list of all links and backlinks in AD and more specifics can be found at the following link:
http://www.neroblanco.co.uk/2015/07/links-and-backlinks-in-active-directory-for-exchange/

Outlook, Autodiscover, and those attributes

When Outlook fires up, and while running, part of what Autodiscover process performs is it will check these two attributes to determine if there are any shared mailboxes that must be automatically added to the Outlook profile. In some cases using a managed process for shared mailboxes, we may want this feature disabled so the shared mailbox does not get automatically added.

Orphaned Backlink is still populated and the mailbox still shows up in Outlook

If the user was previously delegated to a shared mailbox, then the delegated per,missions were removed, but for some reason, perhaps replication or corruption, or some other unforeseen factor (large environments fall under this category), the shared mailbox still shows up and you can’t get rid of it, and further, since you no longer have permissions, you can’t open it. This will cause the shared or delegated mailbox to still show up in Outlook. But you can clearly see in EAC or running a get-mailboxpermission that the user is no longer delegated.

Example of an account with the msExchDelegateLinkListBL still populated:

How to remove it?

First, establish your PowerShell session to Exchange OnPrem or your Office 365 tenant. If unsure how, see this:
http://blogs.msmvps.com/acefekay/2017/05/11/establishing-a-powershell-session-to-your-office-365-tenant-or-onprem-exchange/

Determine, if any, links or backlinks exist on the shared mailbox:

Get-ADUser “SharedMailboxDisplayName” -Properties msExchDelegateListLink | Select-object -ExpandProperty msExchDelegateListLink

If any show up, you’ll see their sAMAccountNames. If you don’t know who the sAMAccountNames are and you want to see their displayNames, run the following (this command works for DNs, too):

For one account:
get-aduser sAMAccountName -Properties displayName,mail | ft Name, DisplayName, mail -A

For a list of accounts in a text file:
get-content c:\temp\names.txt | get-aduser -Properties displayName,mail | ft Name, DisplayName, mail –A

Then remove the msexchDelegateLinkListBL orphaned backlink and FullAccess permissions to the shared mailbox

Note: I’m using the shared mailbox’s displayName. This will also work using the sAMAaccountName or the primary email address.

For one account:
Remove-MailboxPermission “SharedMailboxDisplayName” -user $_ –AccessRights FullAccess -Confirm:$false

For a list of accounts in a text file:
get-content c:\temp\ace\userIDs\users.txt | foreach {Remove-MailboxPermission “SharedMailboxDisplayName” -user $_ –AccessRights FullAccess -Confirm:$false}

Then if needed, delegate the shared mailbox again & disabling Automapping

Delegate Ace to a shared mailbox:
Add-MailboxPermission “Shared Mailbox Name or email address” -User AceFekay@contoso.com -AccessRights FullAccess -AutoMapping:$false

To just remove the backlink WITHOUT removing permissions

Note, using this method, the shared mailbox will automatically disappear from the Outlook profile. As soon as it does, you must manually re-add the shared mailbox either under the user account properties, where the permissions are proxied through the user account, which is the same as if it were Automapped, or as a separate account, which provides better features including sent and deleted items go into the shared mailbox itself instead of the mailbox owner under an automapped account or added under the user account.

To remove all BLs all at once:

#########################################################
#Remove the MSExchDelegateListBL from an account

$userToClean = “I061859”
$userDN = Get-ADUser $userToClean | select -ExpandProperty DistinguishedName
$delegates = Get-ADUser $userToClean -Properties msExchDelegateListBL | select -ExpandProperty msExchDelegateListBL
Write-Host “======================================================”
write-host “List of Delegated accounts that are backlinked:” $Delegates
Write-Host “======================================================”
foreach ($delegate in $delegates) {
Set-ADUser $delegate -Remove @{msExchDelegateListLink = “$UserDN”}
}
Write-Host “======================================================”
Write-Host “If the following get-aduser cmdlet searching for backlinds is empty, then all delegated backlinks have been removed”
Get-ADUser $user -Properties msExchDelegateListBL | select -ExpandProperty msExchDelegateListBL
Write-Host “======================================================”

To remove specific BLs one at a time:

# 1. Find the list of users in a shared mailbox that have been backlinked.
# Note, as said, this is only for removing users that have requested it, unless you are working on removing all, which use the above

$SharedMailboxOrUserDisplayName = “Shared Mailbox Display Name”
$SharedMailboxOrUser = (get-recipient “$SharedMailboxOrUserDisplayName”).name
Write-Host “======================================================”
Write-host “Shared Mailbox sAMAccountName:” $sharedMailboxorUser
Write-host “List of Users (or ‘Delegates’) that currently have Backlinks on Shared mailbox ‘$sharedMailboxorUser’ :”
Get-ADUser $SharedMailboxOrUser -Properties msExchDelegateListLink | Select-object -ExpandProperty msExchDelegateListLink | get-aduser -Properties displayName,mail | ft Name,DisplayName,mail -A
write-host “======================================================”

# 2. Then enter the user account name from the above list that you want to remove, and then find the user’s DN:
$UserToClean = “User sAMAccountName”
$userToCleanDisplayName = (get-recipient $UserToClean).displayName
$userDN = Get-ADUser $UserToClean | select -ExpandProperty DistinguishedName
Write-Host “The DN of ‘$userToCleanDisplayName’ ($UserToClean) that you want to clean is: ” $userDN
Write-Host “======================================================”
write-host “List of Backlink DNs that you want to remove from $UsertoClean :”
Write-Host
Get-ADUser $UserToClean -Properties msExchDelegateListbl | select -ExpandProperty msExchDelegateListBL

Write-Host “======================================================”

# 3. Remove the MSExchDelegateListBL from my account or an account that was migrated to the cloud that previously had a MSExchDelegateListBL
# Just have to run this, the BL gets removed after you run it
# This does not remove any AccessRights to the Mailbox, it just removes the automapping

Set-ADUser $UserToClean -Remove @{msExchDelegateListLink = (Copy and Paste the Backlink DN of the specific shared mailbox from the previous list that you want to remove) }

# 4. Then check to see if it worked:
Get-ADUser $UserToClean -Properties msExchDelegateListBL | select -ExpandProperty msExchDelegateListBL
Get-ADUser $UserToClean -Properties msExchDelegateListLink | select -ExpandProperty msExchDelegateListBL

==========================================================

Summary

I hope this helps!

Published 5/18/2017

Ace Fekay
MVP, MCT, MCSE 2012, MCITP EA & MCTS Windows 2008/R2, Exchange 2013, 2010 EA & 2007, MCSE & MCSA 2003/2000, MCSA Messaging 2003
Microsoft Certified Trainer
Microsoft MVP – Directory Services

As many know, I work with Active Directory, Exchange server, and Office 365 engineer/architect, and an MVP in Active Directory and Identity Management, and I’m an MCT as well. I try to strive to perform my job with the best of my ability and efficiency, even when presented with a challenge, and then help others with my findings in case a similar issue arises to help ease their jobs. Share the knowledge, is what I’ve always learned.

I’ve found there are many qualified and very informative websites that provide how-to blogs, and I’m glad they exists and give due credit to the pros that put them together. In some cases when I must research an issue, I just needed something or specific that I couldn’t find or had to piece together from more than one site, such as a simple one-liner or a simple multiline script to perform day to day stuff.

I hope you’ve found this blog post helpful, along with my future scripts blog posts, especially with AD, Exchange, and Office 365.