I also have been having problems with the same unit (refer to my earlier post). I have been trying to install the NW HD3, MC recognises it, it comes up as a drive, MC will transfer MP3's to it and you can use IE to copy tracks backwards and forwards. Sonic stage rips tracks in the Atrac format and transfers them as same to the handheld. Done this way the handheld recognises and plays them. Despite firmware changes which allegedly make the NW HD3 MP3 compatible (early versions were not), there appears to be no way of changing the Sonic Stage stage to rip/transfer as MP3. MC does not appear to play the Atrac tracks. The Sony support site for the unit explicilty states that the unit will not work with software other than Sonic Stage (but they would wouldn't they!). I persuaded my friend who has the unit to buy MC but he currently has to use Sonic Stage until I come up with a solution.