USB3.0 no assignable to Windows 2008R2 machine

Hi,

I have just updated to ESXi 6.0U3 and wanted to change the USB2.0 controller to a USB3.0 on one VM with a Win 2008R2 in it.

Anyhow, I can neither change the controller, nor can I remove it and then re-add it as USB3.0

The ESX Config Tool only allows me to add USB 2.0 to it.

I also have a Windows Server 2016 and Windows 10 VM, here I can also Assign USB 3.0 controllers.

Why doesn't it work on the VM with 2008R2 in it?

All the VMs are on VM-Version 11 (ESXi6.0)

Any ideas?

Thanks

Stefan