I am having a really nasty problem with VirtualBox as everytime I try to install any guest OS(using ISO file as CD for installation media), the installation starts normally but as soon as it is about to start either installing to virtual hard drive or loading(e.g. as LiveFS) it causes the host system to reboot abruptly. Config is as below: Host system: Ubuntu 12.10 64bit - Intel® Core i7-2640M CPU @ 2.80GHz × 4 Virtualbox version: 4.1.18_Ubuntu r78361 Guest OS systems tried: 32bit version of FreeBSD 9, Debian 6, Tails 0.14 VM setup Tried to have the minimal setup necessary just in case it would avoid for each system to make sure I'd avoid conflicts, but to no avail. I've tried different values and combinations of the below but the problem still persists: Shared Clipboard: Disabled Show in fullscreen/seamless: Disabled Remember runtime changes: DIsabled Base Memory: 2048 MB Chipset: PIIX3 IO APIC: Disabled EFI: Disabled Absolute Pointing device: Disabled Processor(s): 1 CPU PAE/NX: Disabled VT-x/AMD-V: Disabled Video Memory: 12 MB 3d/2d acceleration: Disabled Storage IDE COntroller: PIIX3 (same as chipset instead of PIIX4) Use host I/O cache: No Audio: disabled Network adapter: NAT USB controller: disabled No shared folder Also another sideeffect of the reboot is that it appears that it does not log any information in the error log files; not making things any easier. Please help.