Consider the following scenario:

• On Windows Vista-based computer, you connect a removable storage device, such as a USB device, to the computer. After you do that, Windows Vista assigns a drive letter to the removable device in the system device context.
• You disconnect the removable device from the computer, and then you map a network drive by using the drive letter that was previously assigned to the removable device.

In this scenario, if you reconnect the removable storage device to the computer, Windows Vista cannot find the device.

Note: If you disconnect the network drive, the drive letter is assigned to the removable storage device, and you can access the device.