If the remaining battery power is low or insufficient, charge the battery. If your Walkman still does not operate after charging the battery, press and hold the (Power) button for longer than 10 seconds to restart the Walkman.

The data hierarchy levels of the content such as music transferred by drag-and-drop may not be correct. Place them in the appropriate folder and hierarchy.

Transferred files are not in a playable format. See “Supported formats” for details on playable formats.

When you transfer audio MP4 files by drag-and-drop, place them in the “MUSIC” folder of your Walkman.

The transferred content may be damaged. When you transfer content, make sure that no other tasks are running on your computer until transferring is completed. Otherwise, the content may be damaged. Delete the unplayable content from your Walkman and transfer it again. If the Walkman is still unable to play the content, format the built-in flash memory of the Walkman using the function of the Walkman and then transfer the content again.

If you change the file names or location of the content such as music that was transferred from your computer to your Walkman, the content may not be recognized by the Walkman. Return it to the correct name and location.

If you have initialized (formatted) the built-in flash memory of your Walkman using Windows Explorer, initialize (format) it again using the Walkman. If you have initialized (formatted) the Walkman using the Mac Finder, initialize (format) it again using the Walkman.