VirtualBox (the Qt4 UI, VBoxHeadless and VBoxSDL work) is failing with a segmentation fault when I try to launch it as a non-root user on a x86-64bit/stable/core system. Failed in the same way when I tested on a different minimal install (just core, xorg, lxde, virtualbox). Judging from an strace the problem is with setuid root. The VirtualBox binary from virtualbox-bin works. See this forum thread for more detail. http://forums.funtoo.org/viewtopic.php?id=1582