Thanks, Tom. However... That one liner doesn't do it. If the drive is not mounted it draws an error. > sudo mount -uw "/Volumes/Bonehead" Runt:~ dave$ sudo mount -uw "/Volumes/Bonehead" Password: mount: unknown special file or file system /Volumes/Bonehead. The other USB drive (with 3 partitions) mounts just fine, and it is reported the same way when running plain "mount" (when the problem drive is also mounted)... /dev/disk1s10 on /Volumes/Bonehead (local, nodev, nosuid, journaled) /dev/disk0s10 on /Volumes/Meathead (local, nodev, nosuid, journaled) /dev/disk0s12 on /Volumes/Meathead X (local, nodev, nosuid, journaled) /dev/disk0s14 on /Volumes/Meathead X2 (local, nodev, nosuid, journaled) The problem is that Bonehead does not mount at all when rebooting from OS X back into OS X. If I come from OS 9 (where the drive mounts ok) into OS X, then it will mount. Anything else? Maybe a way to tell disk1s10 to mount? If it helps, here's an abbreviated list (the two USB drives) of what's in /dev/. It's the same whether the problem drive is mounted or not... brw-r----- 1 dave operator 14, 0 2 Feb 19:57 disk0 brw-r----- 1 dave operator 14, 9 2 Feb 19:57 disk0s10 brw-r----- 1 dave operator 14, 10 2 Feb 19:57 disk0s12 brw-r----- 1 dave operator 14, 11 2 Feb 19:57 disk0s14 brw-r----- 1 dave operator 14, 12 2 Feb 19:57 disk1 brw-r----- 1 dave operator 14, 21 2 Feb 19:57 disk1s10 Dave.