Why is AMD-V disabled?

Discussions related to using VirtualBox on Windows hosts.
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eeppeliteloop
Posts: 2
Joined: 5. May 2011, 09:21
Primary OS: MS Windows 7
VBox Version: OSE other
Guest OSses: Debian, WinXP

Why is AMD-V disabled?

Post by eeppeliteloop »

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,
BillG
Volunteer
Posts: 5102
Joined: 19. Sep 2009, 04:44
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Windows 10,7 and earlier
Location: Sydney, Australia

Re: Why is AMD-V disabled?

Post by BillG »

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.
Bill
eeppeliteloop
Posts: 2
Joined: 5. May 2011, 09:21
Primary OS: MS Windows 7
VBox Version: OSE other
Guest OSses: Debian, WinXP

Re: Why is AMD-V disabled?

Post by eeppeliteloop »

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?
BillG
Volunteer
Posts: 5102
Joined: 19. Sep 2009, 04:44
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Windows 10,7 and earlier
Location: Sydney, Australia

Re: Why is AMD-V disabled?

Post by BillG »

Is it enabled here?
VT.PNG
Bill
Sasquatch
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Posts: 17798
Joined: 17. Mar 2008, 13:41
Primary OS: Debian other
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Re: Why is AMD-V disabled?

Post by Sasquatch »

If it is, post a log so we can see where the problem lies. The log usually shows what's wrong.
Read the Forum Posting Guide before opening a topic.
VirtualBox FAQ: Check this before asking questions.
Online User Manual: A must read if you want to know what we're talking about.
Howto: Install Linux Guest Additions
Howto: Use Shared Folders on Linux Guest
See the Tutorials and FAQ section at the top of the Forum for more guides.
Try searching the forums first with Google and add the site filter for this forum.
E.g. install guest additions site:forums.virtualbox.org

Retired from this Forum since OSSO introduction.
Orris
Posts: 1
Joined: 11. Jan 2012, 01:20
Primary OS: MS Windows 7
VBox Version: PUEL
Guest OSses: Ubuntu/Debian

Re: Why is AMD-V disabled?

Post by Orris »

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
bug-me-not
Posts: 7
Joined: 9. May 2014, 00:00

Re: Why is AMD-V disabled?

Post by bug-me-not »

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!
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