Argh. While syncing my music to my SMT5600 the phone crashes after just a few songs are transferred. The phone will not respond to any button presses. The only way to recover from this state of affairs is to remove the battery.
WMP10 just shows that whichever song it was copying when the phone crashed is xx% done without reporting any errors.
My search skills have failed me because I am unable to find anyone else suffering from the same issue!