I am running 9.1RC1: Code: FreeBSD system 9.1-RC1 FreeBSD 9.1-RC1 #0 r240745: Thu Sep 20 08:33:01 PDT 2012 root@system:/usr/obj/usr/src/sys/GENERIC amd64 on a system with this motherboard: GIGABYTE GA-Z68X-UD3H-B3 LGA 1155 Intel Z68 HDMI SATA 6Gb/s USB 3.0 ATX Intel Motherboard Problem 1: I am unable to use the two USB 3.0 ports on the back in FreeBSD. They have worked perfectly in Windows 7 for over a year on the exact same system. When I plug one of my USB drives into the USB 3.0 ports I get: Code: Dec 9 14:01:16 system kernel: (probe0:umass-sim0:0:0:0): CAM status: CCB request completed with an error Dec 9 14:01:16 system kernel: (probe0:umass-sim0:0:0:0): Retrying command Five times before the system gives up. I saw a post sometime ago about setting a USB 3.0 port to run in 2.0 mode which would be fine. But I don't see such an option in my BIOS setup screen or know if that is possible in some FreeBSD setting. Problem 2: The major problem is g_vfs_done() errors that will eventually start showing up after transferring data to one of the drives. The drives still work perfectly for reading even with the constant stream of g_vfs_done error messages, but all future writes immediately return an error. Shutting down cleanly is prevented by the system by the g_vfs_done errors and sometimes it leaves the drive in a bad state that requires me to restart into Windows and run a disk check to fix the errors. Edit: Should have made it clear there are two separate problems.