Looks like I have the same problem. I have upgraded to Lucid Beta 1 recently, after that my external USB HDD has stopped working. Other USB drives works fine though. My dmesg output is very similar to what is reported in this bug (see attachement).
** Attachment added: "dmesg-output" http://launchpadlibrarian.net/41583946/dmesg-output -- rejecting I/O to offline device https://bugs.launchpad.net/bugs/480665 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
