We have a user that when they send out meetings via their calendar they get an error back caused by a user that had been deleted from AD but it seems that their security permissions exist on the mailbox.
Using active directory users and computers I have opened the properties of the user and have click on the advanced exchange tab and then clicked onto mailbox rights. There is a user with permissions to the mailbox called s-1-23-21-253453465-3453345 (or something to this effect) with a question mark over the icon. When I try and remove this it says that I have to remove the inherited permissions before removing the object, but I can find no way of removing the inherited objects.
