I created a new virtual machine, I wanted to try running ubuntu 10.12 64 bit iso. I used the default parameters. version: ubuntu 64 bit Boot Disk: Creates hard disk File Type: VDI dynamically allocated I changed the option: Enable Efi ON ERROR LOG:I'm using a hp pavilion i5, I have to touch something at the level of Bios, can someone give me explanations? heartfelt thanks [RESOLVED]: BIOS, virtualization enabledCode:VT-x/AMD-V hardware acceleration has been enabled, but is not working. The 64-bit guest will fail to detect a 64-bit CPU and will not start. Make sure you have correctly VT-x/AMD-V enabled in the BIOS of the host computer.