Had this strange popup trying to remove an old Exchange user and it referenced a CN=iPhone in the error. I assume its something Exchange created for the iphone, but here is how I got rid of it:
- Fire up ASDIEdit.msc and open the default naming context
- Drill down to where the user is stored in AD and you’ll find a container underneath the user
- Right-click on the item in the folder and go to Properties
- Take ownership of the object, reopen and then you can give “Authenticated Users” full access to it (since we’re deleting)
- Now you should be able to able to delete the user