virtualbox.org

Hi. I am using VirtualBox 4.0.6 (as an "administrator") on a Windows 7 64-bit host with Debian 32-bit and WinXP 32-bit guests. For both of them, I enabled AMD-V support. When I launch any of them, I see that AMD-V is not active. Yesterday, I was still using WinXP 32-bit on the same computer, with VirtualBox 4.0.6, and with the same guests (actually I created new ones but I mean with the same guest systems), AMD-V was active (it's enabled in the BIOS and everything; it worked yesterday).

Is it the 32-bit to 64-bit transition? Is it something special regarding Windows 7? May AMD-V be enabled when virtualizing a 32-bit guest on a 64-bit host?

Please help, I'm clueless.

Thank you,

Whether hardware virtualization is enabled or not depends entirely on your hardware and you BIOS. It is not affected by what OS you are running. Check the BIOS settings again.

32-bit guests will run without it. 64-bit guests will not.

I double-checked my BIOS and Virtualization is enabled. Also, the AMD-V Hyper-V Compatibility Check Utility tells me AMD-V is enabled and functional. However, when I launch a guest, the AMD-V icon in the bottom status bar says it's disabled. Why?

Is it enabled here?

If it is, post a log so we can see where the problem lies. The log usually shows what's wrong.

I googled this and found this post which seems a little open ended.

I had the same problem and i found that if you have selected Multiple CPU cores it enables VT-x/AMD-V even if you untick it as an option.
Still not sure why it does it when it is enabled in Bios, but thought i would quickfix for now and figure the rest out later

Also came across this problem with another source: Giving to much RAM to a 32bit guest!
RAM+GPU-RAM may not be >= 4096, test with 1GB if this is your cause, then reduce RAM until it works!