While charging your Nuvi with your PC/laptop, you can use it by following 2 simple steps:
1. Left-click the "Safely Remove Hardware" icon at the bottom right of your screen. If the icon is not visible, click the arrow icon to display all icons.

2. Select "Safely remove USB Mass Storage Device - ...."

If you have more than one removable storage device connect, say a card reader, please ensure you remove the correct drive.