How to delete MAPI Permission if Remove-MailboxFolderPermission does not work

Andres Bohren

2022-12-30

Hi All,

Today i helped a Collegue with an Exchange Online Folderpermission Problem. He could not remove the Permissions from a Mailbox Folder (MAPI Permission).

Get-MailboxFolderPermission -Identity email@domain.tld:\Kalender | fl

Let’s remove the User (In fact a Mail Enabled Security Group)

Remove-MailboxFolderPermission -Identity email@domain.tld:\Kalender -User CH_DE_Room_Equipment_Reviewer

This resulted in the following Error: Microsoft.Exchange.Management.StoreTasks.UserNotFoundInPermissionEntryException | There is no existing Permission entry found for user

I’ve grabbed MFCMAPI from Stephen Griffin.

First set some Options Tools > Options

Enable the two Options:

Use the MDB_Online flag when calling OpenMsgStore
Use the MAPI_NO_CACHE flag when calling OpentEntry

I’ve created an Outlook Profile and had FullAccess to that Mailbox.

Session > Logon

Selected that Outlook Profle

Selected the Mailbox

Selected the Top of Information Store > Kalender Folder

With the right click i opened the Context Menu and selected > other Tables > ACL Table

Here i was able to delete the Entry

Regards
Andres Bohren

Andres works as a Senior Microsoft Cloud Engineer/Architect for midsize to large Enterprises at isolutions in Switzerland. He has a special focus on M365 including Identity, Messaging, Communication, Security and PowerShell but also some Azure Technologies. He is Co-Organisator of the Microsoft 365 Community Schweiz Meetup group and was Speaker at several other Meetups or Conferences. He likes good Food, his Bike and nice Dive spots all over the World.