vSphere/ESX 5.5 updates 1 and 2 do not have support for true Windows 10 VMs. VMware recommends you create a Windows 8 VM and then install Windows 10 in it.  Unidesk does not support that kind of hybrid approach.  Unidesk will let you import the OS layer from such a machine, but when we go to create a Windows 10 desktop or IM, we try to create a proper Windows 10 VM, which is not available on the host. The task will fail with an error from vSphere when trying to create a VM.

The virtual infrastructure failed to create a virtual machine. Error is: Error received from VMWare while waiting for requested data.
FaultType: InvalidArgument
Message: A specified parameter was not correct.

You need to upgrade to a version of vSphere that explicitly supports Windows 10 VMs. 

While VMware will provide support for Windows 10 as a guest OS on a VM on 5.5 (any update), the VM will always have to be created as a Windows 8 machine. Only 6.0 and 6.0 u1 actually let you select Windows 10.

From VMware:

During the guest OS configuration process, when selecting the Guest OS, Windows 10 selections are available for VMware vSphere 6.0, VMware Workstation 11, VMware Fusion 7 and later releases. For VMware vSphere 5.5, if a Windows 10 option is not available, select Windows 8.