I managed to solve this matter when it occured in dec 2008. But it costed me all my tunes on the player. Luckily I always have a back up because I usually have to convert from mp4 to mp3. So I get a spare playlist in mp3 wich I put on my external harddisc.
Now I got this error again and the only solution for a mac user is to if you can format the disc to msdos fat 32 if the mac has that option.
I also always use the “copy cat” for mac when uploading music.
My lesson as a mac user dealing with sansa fuze is to be very careful when uploading and always keep a good reserve of space on the sansa.
But I wonder has it come there a way to restore the sansa without formatting the player since december 2008 or is the sansa still mainly for windows users?