USB Devices Disconnect from Guest Operating System During Snapshot and Power Operations

Products

• VMware Desktop Hypervisor

Issue/Introduction

Why does my guest operating system lose connectivity to any USB devices it was using when I take a snapshot or revert to a previous snapshot, or when I suspend and resume the virtual machine?

Environment

VMware Workstation 4.x (Windows)
VMware Workstation 5.x (Windows)

Resolution

The answer depends on the version of Workstation you are using, as described in the following sections.

Workstation 5.0 and Earlier Versions

In Workstation 5.0 and earlier versions, it is not possible for the virtual machine to remember the connection status of USB devices when you take a snapshot or revert to a snapshot, or when you suspend a virtual machine. To accommodate this limitation, Workstation 5.0 and earlier versions disconnect any USB devices from the virtual machine for power and snapshot operations.
To reconnect USB devices that disconnect from the virtual machine after you take or revert to a snapshot, or after you suspend a virtual machine:

1. Power on the virtual machine.
2. In the Workstation window, choose VM > Removable Devices > USB Devices, then select the device you wish to reconnect.
3. 
   
   Note: If the device isn't listed in the USB Devices menu, physically disconnect the USB device and reconnect it.

Workstation 5.5

In Workstation 5.5, when you attach a USB device to a virtual machine through the VM menu (VM > Removable Devices > USB Devices), the virtual machine remembers the USB device and automatically reattaches the USB device after a snapshot or power operation if the device is available. If the device is not available, a message appears, indicating that the USB device could not be connected and that the virtual machine will no longer try to connect that USB device. To manually prevent the virtual machine from remembering the USB device, remove the USB device from the virtual machine through the VM menu.

Note:

• Workstation remembers the USB device by the host port to which the device is attached, and not by any USB device-specific value (descriptor string, VID/PID, or serial number). If you connect a USB device to a virtual machine manually, then suspend and resume, take a snapshot, or revert to a snapshot, and finally replace the physical USB device with a different USB device on the same host port, Workstation automatically connects the new device to the virtual machine.
• If you plug a USB device into the host while the virtual machine has focus, Workstation does not remember nor autoconnect the device after power and snapshot operations. To have Workstation remember and automatically reconnect a USB device, you must connect the device through the VM menu.
• After you manually connect a USB device through the VM menu, Workstation still remembers the USB device port if you unplug the USB device from the host while the device is connected to the virtual machine.