After installing some updates, the problem went away. Based on which updates were installed it looks like Cyril Jaquier was right about the diagnosis.
** Changed in: virtualbox-ose (Ubuntu) Status: New => Fix Released -- Virtual Machine Won't Start - Kernel driver not installed https://bugs.launchpad.net/bugs/449936 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