The partition and formatting on a USB flash memory drive is sometimes a bit faulty. Symptoms include (but are not limited to) FreeBSD complaining about the start and/or end of the partiton not being on a track boundary, the total number of sectors not being a multiple of the number of tracks, the drive not being recognised especially in MS Vista and errors when saving files in Windows. If you have a malfunctioning USB stick try this: Copy off any files you want to keep. (important) Plug in the stick and check what device it is recognised as. It's usually da0 if you don't have any SCSI drives. But CHECK. Now remove the existing partiton information: # dd if=/dev/zero of=/dev/da0 bs=2m count=1 Create a new slice/partiton # fdisk -i /dev/da0 In the interactive section accept the defaults except for sysid, which is 165 for FreeBSD but for FAT32 is 12. Ignore the 'fdisk: Class not found' error. Create a new file system ('format') # newfs_msdos -F32 /dev/da0s1 Enjoy working USB drive.