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

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

Andres Bohren