Since upgrading to 8.5, the Remote Assistance option is always grayed out
To turn on remote assistance
1. Open the vWorkspace Management Console.
2. Right click on Locations
3. Click on RDP Connections
4. Tick the "Enable RDP remote administration control"
5. Click OK
Remote assistance will now be an option again.
Because of a Microsoft platform limitation, remote assist is not supported on computers running RDP8 (Windows Server 2012, Windows 8 and potentially Windows 7 Service Pack 1 with the RDP8 Client installed).