I have a Western Digital 2TB USB drive. Its format is msdosfs. My base system and ports are up to date as of today. Code: FreeBSD 9.0-STABLE FreeBSD 9.0-STABLE #0: Thu Apr 26 03:00:17 PDT 2012 user@:/usr/obj/usr/src/sys/GENERIC amd64 Attempts to write to the drive will either work for a few small files and then fail or outright fail immediately. After write failure an endless stream of: Code: kernel: g_vfs_done():da1s1[WRITE(offset=-886695100416, length=32768)]error = 5 is generated in /var/log/messages. I have run smartctl tests on the device and they show: Code: === START OF READ SMART DATA SECTION === SMART overall-health self-assessment test result: PASSED I have used the drive extensively in Windows with no read or write errors and have run the system drive check on the drive multiple times with no errors reported.