Ok - the problem was my fault. The USB device has a connector that does not fasten very securely. If it is partially in, the device will receive power, but not transmit data to the machine. I haven't had any problems since noticing this.
So this bug can be closed/removed. I would do it myself, but I can't seem to find the close button. -- USB Hard drive is not always detected/mounted https://launchpad.net/bugs/47617 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
