virtualbox.org

Hello,

I'm having trouble getting VirtualBox to run a 64-bit Cent OS machine.

The error I'm getting is:
"VT-x/AMD-V hardware acceleration is not available on your system. Your 64-Bit guest will fail to detect a 64-bit CPU and will not be able to boot."

My machine is a Dell Optiplex 960 with a Intel Core 2 Due CPU E8500. All of my BIOS settings seem to show that virtualization is turned on:

Virtualization Support
  Virtualization: on
  VT for Direct IO: on
  Trusted Execution: on

Under my BIOS security settings, I've enabled TPM Security (although I'm not really sure what it does). I didn't see any other security settings that might affect virtualization. I ran Intel's Processor Identification Utility, and it reports that Intel VT-x with Extended Page Tables is NOT supported, but that's contrary to what I've found online. In the same report, Intel Virtualization Technology and 64 Architecture are both supported. I've included screen captures in a zip file attached to this posting.

Any ideas what's going on?

Thanks,
Bret

1) 64-bit guests need hardware-virtualzation enabled in the hosts bios.
2) when creating the 64-bit guest you must select 64-bit in General -> Basic -> version.
3) If running Windows as host you must make sure hyper-v or xp mode is not enabled on the host. MS does not play well and wants it all.

Sounds like 3) is what is causing you issue.

Thanks Perryg,

I think I have solved the issue. I believe it was a setting in my BIOS. There was some setting about restricting applications that could cause stack overflows (or something - I can't recall exactly). After disabling that feature, shutting down my computer, and restarting, it seems to have solved that issue.

Cheers,
Bret