I wonder if that is a dup of bug 1686324 - the message your case reports is slightly different, but those could change with versions.
To check that I'd ask you to - after starting the failing guest - check your dmesg if you have any apparmor Denials? If so please report them here so we can check if this is a known issue. Please also report back if you have no related apparmor Denials so we can discuss about other potential reasons. ** Changed in: libvirt (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1708013 Title: USB passthrough not working: failed to find host usb device 1:2 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1708013/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs