What is the reason why all files or songs transferred under MTP to a sansa always shows under Properties as 3/31/2005 under date modified? I have tested it with Fuze, CLip+ and e250 v2 with all update firmware and I get the same information. Under MSC tho it shows the right information for date modified. Is it because MTP drivers was actually release 3/31/2005 which I doubt since I have a MTP mobile phone at the date modified is correct.
I also experienced this problem and from what I read online it requires the device clock to be reset, although having tried all the steps recommended (using wmp after an msc format to get the prompt, using rhapsody to reset secure clock, performing the steps on internet explorer indicated on a sansa help page) none of these worked.
Really I think if you have this problem then the only option is to use msc mode if you want any proper sync info functionality.