unable to mount USB hard drive

I recently upgraded my netbook from Ubuntu karmic 9.10 to 10.04 LTS, after which I upgraded the installed Trinity 3.5.11. At first everything seemed to be Just Fine. But, I found that when I attempted to connect my external USB hard drive it resulted in a pop-up error message: Method "Mount" with signature "ssas" on interface "org.freedesktop.Hal.Device.Volume" doesn't exist The same USB hard drive mounts (and unmounts) Just Fine on my older karmic 9.10 box with Trinity 3.5.11. (The drive is formatted ext3 and I use it to back up $HOME(s) on my linux boxes.) The netbook is remembering something about the mount attempt, because after a cold re-boot, _without_ the USB drive connected, there remains a mount point: /media/MLJ_USB_1/ -- "MLJ_USB_1" being the label of the USB hard drive. And I cannot `umount` it: "... is not mounted (according to mtab)". `mount` shows: "/dev/sda1 on / type ext4 (rw,errors=remount-ro)" -- of course the USB drive is NOT connected at all. (The USB drive shows properly as "/dev/sda5 / _ext3_ rw,errors=remount-ro 0 0" on the karmic box.) If I log out of Trinity and into Gnome, I can mount and unmount the drive without a problem. If I leave it mounted -- log out of Gnome and log back into Trinity, it is still mounted, and shows as formatted ext3. If I then (in KDE) unmount it, unplug it, and plug it back in, I get: Method "Mount" with signature "ssas" on interface "org.freedesktop.Hal.Device.Volume" doesn't exist Looking through the Bug List does not yield anything that fits my problem. Then, being paranoid, I checked to see if the same problem existed with the SD memory card socket. Yes, same problem. And, the SD card mounts and unmounts Just Fine in Gnome. What to do? Thank you, Jonesy -- Marvin L Jones | jonz | W3DHJ | linux Pueblo, Colorado | @ | Jonesy | OS/2 __ 38.238N 104.547W | config.com | DM78rf | SK