Hi all, I recently deleted a Security Group from our W2k DC. This Group was added to some public folders on our Exchange 2000 server. When I open a permissions dialog from a Public folder on a Mapi client the dialog shows a SID number for the delete group. In the past I was always able to delete these SID numbers from the permissions of a public folder. But now for some reason it fails. It even fails on the Exchange System Administrator saying: ?invalid window handler?. To make things worse; I delete the SID entry from the public folders with help of the installable file system on the M drive. After I had done this I read somewhere that you never should change the permissions on a public folder with the help of the installable file system. Does anyone know how you can somehow reset the permission on a public folder, so that a Mapi client can edit the permissions again? Many thanx !!!