You may see this issue if you plug in a removable device (such as a flash drive or external hard drive) and:
- Windows recognizes the device and installs necessary drivers
- Windows reports the device is ready to use
- Windows does NOT show an icon for the device in “My Computer”
- The device works fine in another computer
Assuming that device drivers are not the issue (see #1 above), you may have a situation where Windows is not assigning a drive letter because the previous drive letter is in use by something else (such as a mapped network drive, etc) or not automatically assigned / configured. In this case, you have to manually assign the device an unused drive letter.
- Click Start > Control Panel
- Double-Click Administrative Tools
- Double-Click Computer Management
- On the left pane, expand Storage if not already, and select Disk Management
- On the top pane, under the Volume column, locate the device with no drive letter assigned to it and right-click in the space where the drive letter should appear.
- Select Change Drive Letter & Paths
- Click Add then Assign the following drive letter (select a drive letter) and Ok
Once the device has been assigned a drive letter it should resume normal operation.