View 6 - Add Server 2008 R2 Desktop to pool - "VM with unsupported Guest OS"

Hi,

I need to install a new View Connection Server because we upgraded the vCenter Server to 5.5 and View does not allow the migration to a new vCenter Server.

So my plan is to "unplug" all desktops from the old View Connection Server (if necessary) and add them to the new View Connection Server.

We use some Server 2008 R2 desktops but if I try to add them to the inventory View tells me "VM with unsupported Guest OS".

How can I add them to the pool / inventory?