I'm using the hostusb hook on RHEV 3.4 trial. The usb device is passed through to the VM, but I'm getting errors in a Windows VM when the device driver is loaded. I started with a simple usb drive, on the host it is listed as: Bus 002 Device 010: ID 05dc:c75c Lexar Media, Inc. Which I added as 0x05dc:0xc75c to the Windows 7 x64 VM. In Windows I get an error in device manager: USB Mass Storage Device "This device cannot start. (Code 10)" Properties/General Tab: Device type: Universal Serial Bus Controllers, Manufacturer: Compatible USB storage device, Location: Port_#0001.Hub_#0001 Under hardware Ids: USB\VID_05DC&PID_C75C&REV_0102 USB\VID_05DC&PID_C75C So it looks like the proper USB device ID is passed to the VM. I don't see any error messages in event viewer, and I don't see anything in VDSM logs either. Any help is appreciated. Steve