Since 6 months that I have, I've always had bad recognition problems under Windows (XP or Seven), impossible to disconnect itself from the Windows USB Device manager, freeze late transfer for several minutes. In short not reliable ... And I just found a solution => Format key "exFAT" extended format and derived from FAT32 to enable to store files> 4GB, etc. when I had made the choice to NTFS since. And there it is day and night, everything works perfect for 2 days!
Voila hoping to have helped those who have the same kind of problems that the air current on key> 16GB with certain controller.
So if you have problems, try formatting in exFAT instead of NTFS !!