If you installed XenApp 6, you probably noticed that you’re not allowed to connect via remote desktop to farm’s servers with non administrative users. The error message is: the desktop you’re trying to open is currently unavailable
The cause is a default policy for all the users.
Open Delivery Services Console and choose Policies node.
Change to User tab, choose Unfiltered policy and click Edit…
Choose All Settings and, with the help of the search box, find Deskop launches setting:
Choose Allowed and hit ok: