Acronis True Image Server 9.1 mounted images are unseen in File Explorer under Win Server 2008

My Problem:
I am working with Acronis true Image Server 9.1 under Windows Server 2008.
Backup works fine. When I am going to mount a tib-File (wich contains a partitiution as well) the Program tells me, that the image is successfully mounted. But it is not seen in the File Explorer, so I can´t see any things of the mounted Image.

There are no problems in the Hardwaremanager. There the Image is seen as a partitition but not in the File Explorer.

Thanks and Greetings to all of you