Windows Media Player can delete digital media files in a playlist folder, but cannot delete other types of files. Non-digital media files in a playlist folder do not appear in Windows Media Player.
If non-digital media files are stored in a playlist folder, the playlist cannot be deleted. Use My Computer to locate the folder where the playlist that you want to delete is stored, and then delete or move the non-digital media files from it. After you remove the non-digital media files from the playlist folder, you can delete the playlist.
It is recommended that you store only digital media files in playlist folders to avoid this problem.