You can connect your phone to a computer with a USB cable, to transfer music, pictures, and other files between your phone’s SD card and the computer. When connecting your phone to a computer and mounting its SD card, you must follow your computer’s instructions for connecting and disconnecting USB devices, to avoid damaging or corrupting the files on your SD card.

You can’t share your phone’s data connection and SD card via USB at the same time. If you are using USB tethering, you must turn that off first.

Use the USB cable that came with your phone to connect the phone to a USB port on your computer. You receive a notification that the USB is connected. Open the Notifications panel and touch USB connected. Touch Turn on USB storage in the screen that opens to confirm that you want to transfer files.

When the phone is connected as USB storage, the screen indicates that USB storage is in use and you receive a notification. Your phone’s SD card is mounted as a drive on your computer. You can now copy files to and from the SD card. For more information, see the documentation for your computer.

During this time, you can’t access the SD card from your phone, so you can’t use applications that rely on the SD card, such as Camera, Gallery, and Music. You also can’t share your phone’s data connection with your computer via USB.

To disconnect your phone from the computer first Unmount the SD card on your computer. Open the Notifications panel and touch Turn off USB storage. Touch Turn off USB storage in the screen that opens.

Carefully follow your computer’s instructions to unmount the SD card and disconnect USB devices correctly, to avoid losing information on the card.

Google Android 2.2 User’s Guide