Snow Leopard reads NTFS and with Paragon's NTFS for Mac can write. What OS do you use that needs to support the key? And all my keys including the Sandisk Contour 32GB are formatted for FAT32. The only real problem occurs if you have a file larger than 2GB. cjc On 15/05/2010, at 7:54 AM, Matevž Markovič wrote: > Thank you for your help. I just decided to format the key - it is not worth to loose my data because of an unclean file system. > Since the only valid common filesystem is Fat32, I am stuck with it - NTFS does not come into consideration because of limited support on other systems. > Thank you! > Matevz Markovic