It is not. You can open the drive through the Disk Management application and see the drive contents there. Inconvenient, but a workable solution.
I googled for a solution beyond reassigning the drive letters, which seems to be most of the results. There was a small note in one forum that suggested tying all your USBs to a single drive letter and adding them separately as folders.
Rather than assign mine to a single letter, I kept the distinct letters and setup a folder in My Documents labeled USB. Inside the Disk Managment application, right-click the drive and select:

Select the Add button:

Select Browse to locate folder to assign this USB drive to:

Expand tree and select the folder or create a new folder to assign this drive:

Select OK and open Explorer to the folder you just assigned. You should now see the contents of your USB.
