Your “WALKMAN” is not recognized as USB storage.

The USB connection is turned off.

• Swipe the status bar, then tap [USB connected] on the notification panel followed by [Turn on USB storage] then [OK].

USB debugging is enabled.

• Some devices or software may not recognize your “WALKMAN” when USB debugging is enabled. Tap the (Menu) button, then tap [ Settings] - [ Applications] - [Development] - [USB debugging] and uncheck the box.