I am running ESXi 5 and have been successfully using USB Redirection from the vSphere Client to my VM's on this installation of ESXi, this desktop, and the same VMs but it just stopped working. I have done no updates, no reboots, no reinstalls of any kind with the VMs or ESXi although I cannot guarantee that Microsoft didn't udpate something on my Windows 7 Pro desktop since the last time I passed a local USB device to a VM. I have uninstalled and reinstalled the USB Controller on the VM. What else can I try to solve this problem?