Opensuse 13.1 guest will not boot on OpenSuse VirtualBox host

I have been made several attempts to upgrade a VirtualBox guest from OpenSuse 12.3 to 13.1 since 13.1 was released, but cannot get the upgraded guest to boot. I've also tried installing a brand new guest as 13.1 and it won't boot either. I have 13.1 running under VirtualBox on a Windows 7 host just fine. However, 13.1 will not run under an OpenSuse host.

Currently, I'm running a fully patched OpenSuse 13.1 host with VirtualBox rpm VirtualBox-4.3-4.3.12_93733_openSUSE123-1.x86_64 installed along with the matching guest extensions. I updated my guest from 12.3 to 13.1 this morning and the installation completed successfully. However, the updated guest fails to boot. The initial graphical screen keeps restarting over and over again infinitely. I found another thread about this from February that recommended using a community version of VirtualBox, but that won't even begin to boot because of missing support for USB 2.0 and no available guest extensions for that version of VirtualBox.

I have tried this on two completely different physical machines: one with an 8 core AMD processor, the other with a dual core Intel processor and the results are the same with both.

How do I troubleshoot and resolve this problem?