Just sharing a bit of knowledge recently-gained knowledge. If you accidentally attach a device to sys-usb that you shouldn't have, Qubes may refuse to boot.
Here's how to fix the problem: 1) Boot into Recovery/Rescue mode from the Qubes Install USB 2) Qubes will mount your drive after you enter your LUKS password 3) Edit your /var/lib/qubes.xml file to remove all entries from "pcidevs=" for your sys-usb (note that it is not sufficient to turn off auto-starting, the system still will not start) If Qubes Recovery/Rescue doesn't automatically mount your LUKS drive 1) Boot Fedora on live USB 2) Follow the instructions here to mount your LUKS-encrypted disk https://alvinabad.wordpress.com/2012/09/22/how-to-recover-a-luks-encrypted-disk/ 3) Edit your /var/lib/qubes.xml file to remove all entries from "pcidevs=" for your sys-usb -- You received this message because you are subscribed to the Google Groups "qubes-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to qubes-users+unsubscr...@googlegroups.com. To post to this group, send email to qubes-users@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/qubes-users/997accc2-d4c1-4f7c-ba6e-3242adff244f%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.