older post i know, but any luck on a resolution? we just implemented view 5.1 (with unidesk on top) and have the same behaviors for users connecting to a floating pool. first time connection is ok, at logoff the machine resets and then you receive the 'no protocol available' message.
what's also odd is that when a machine is in this state, i can not restart it via vcenter, errors with
"Call "VirtualMachine.RebootGuest" for object "VDI-PoolTest-01" on vCenter Server failed."
and this will affect every desktop in the pool. Once i do a reset from inside view mgmt to all computers., it will work again until a user logs off the next time.
it feels like a config problem in the floating pool, but haven't figured it out yet. will be opening a ticket with VMware soon.
oh, and i had bumped vram to 128, and there are no errors in the logs on the client side.