NT Server hangs at shutdown if User Manager is running.

A. A. This is caused by an Exchange dll file which is used by User Manager, to fix this perform the following

1. Start the registry editor (regedit.exe)
2. Move to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Network\UMAddOns
3. Click on Mailumx and click the DEL key
4. Click yes to the confirmation