They've stopped locking their new models to horrid iTunes-type software. But if you have an older one, I'm afraid you're stuck -- suggest downloading latest version from Sony site if you don't have the original CD that came with the player.
I've had this mp3 player for awhile, and Sonic Stage stopped working so I removed it from my computer. I was stuck with the songs I had on my mp3 player, and they worked fine. Today I had the idea of just clicking and dragging files to my mp3 player's "Music" folder from My Computer. It seemed to work, and I deleted all my old songs off the mp3 player. I then unplugged my mp3 player from my computer, and tried to play the songs. "FILE ERROR" showed up on the screen and all the songs and artists were "Unknown." I searched (the magnifying glass) by both artist and song and all of my old music files were listed, but when I selected one to play, the artist and song were both "Unknown" and "FILE ERROR" showed up again. I've tried quite a few times to reset it, even held the reset button down for over 30 seconds but nothing has happened and the new songs don't show up on it, even though, when I plug it into the computer, I can play songs from the mp3 player's music folder on my computer. It shows that they are there. I don't know what's wrong and would rather not get a new one. Is it hopeless? If I can just find out how to reset it, I will be happy. It's a NW-E002BC Walkman.