the Garmin USB drive may need to be mapped on the computer. This can happen if there are multiple hard drives or network drives on the system.
To map the drive:
1. Click Start.
2. Mouse over Settings, then click Control Panel.
3. Double-click Administrative Tools.
4. In the Administrative Tools window double-click Computer Management.
5. In the Computer Management window, double-click Storage, then Disk Management.
6. Click to highlight the Garmin removable disk drive (either the internal memory or the SD Card drive).
7. Right-click and select Change Drive Letter and Path.
8. Click Edit, select a drive letter from the drop-down list, then click OK.
The drive now appears correctly.