Quick heads up - virtualbox needs couple fixes which are not yet in upstream 4.3.14 in order to compile against 3.17. There are patches here: https://forums.virtualbox.org/viewtopic.php?p=296650#p296650 The patch file I used was : virtualbox-alloc_netdev.diff.txt I have tested the module version of this and confirm it works with 3.17.rc3 custom kernel and that virtualbox comes up and can boot a windows vm. Regards, gene