try and see whether you still can view your file on the Mac . If yes means you have to check whether is the way you format your flash drive (ntfs or mac )
I have a SanCruz 4gb flash drive. I mainly use it on a PC (Windows XP). I printed files saved on my flash drive from a Mac computer, and now when I connect the flash drive to my PC, it says that the drive has not been formatted. I don't want to lose any of the files I have on the flash drive, is this possible? Or will I have to format it and basically start from scratch?