Virtualization Conflict?

[Cluster-Lizard2014]

I'm now on a new Win7 Pro SP1 64 bit PC and I've been looking into installing WinXP Pro 32 bit using virtualization of some form. As my Intel CPU supports virtualization technology I thought finding out about using that would be a good first step. Whilst doing this I came across a problem when investigating system requirements and how to install Windows XP Mode.

The use of the Microsoft HAV Detection tool was recommended to determine whether the system is suitable, has VT support and if it is enabled. When I ran the tool it kept on repeating the message that VT wasn't enabled on this PC. Problem is it is. The BIOS clearly show Intel VT: Enabled.

After a bit of research I found a reply on the well known TomsHardware forums that suggested turning off AVAST's hardware assisted virtualization (AVAST Settings > Troubleshooting) would resolve the issue. I did that, rebooted and, voila, the MS HAV tool now reports correctly about the VT status.

Can someone here explain this because it is perplexing that disabling a setting in AVAST obviously affects whether the whole system is seen as having VT enabled or not. What is the connection? Of course I'm also concerned about running into any other problems because of AVAST if I go ahead with this project.

Advice/comments appreciated.

[Asyn]

Update to the latest version (12.1.2272): https://forum.avast.com/index.php?topic=187663.0

[Avast-TS]

Avast is using VT-x feature of your Intel CPU to provide better security, but unfortunately the use of this resource is exclusive. Please note that Avast will automatically stop using VT-x if other virtualization SW (like VirtualBox) is installed on machine.

I'm now on a new Win7 Pro SP1 64 bit PC and I've been looking into installing WinXP Pro 32 bit using virtualization of some form. As my Intel CPU supports virtualization technology I thought finding out about using that would be a good first step. Whilst doing this I came across a problem when investigating system requirements and how to install Windows XP Mode.

The use of the Microsoft HAV Detection tool was recommended to determine whether the system is suitable, has VT support and if it is enabled. When I ran the tool it kept on repeating the message that VT wasn't enabled on this PC. Problem is it is. The BIOS clearly show Intel VT: Enabled.

After a bit of research I found a reply on the well known TomsHardware forums that suggested turning off AVAST's hardware assisted virtualization (AVAST Settings > Troubleshooting) would resolve the issue. I did that, rebooted and, voila, the MS HAV tool now reports correctly about the VT status.

Can someone here explain this because it is perplexing that disabling a setting in AVAST obviously affects whether the whole system is seen as having VT enabled or not. What is the connection? Of course I'm also concerned about running into any other problems because of AVAST if I go ahead with this project.

Advice/comments appreciated.

[Cluster-Lizard2014]

Thanks for the replies, particularly the latter if that is correct. I certainly hope it is. 

[DavidR]

Thanks for the replies, particularly the latter if that is correct. I certainly hope it is. 

I would hope it is too, given it is from an avast Team member (though not shown in the profile details of the post) at Tech Support (presumably).

[Cluster-Lizard2014]

Sorry the username didn't register with me I just saw the "Newbie" in the forum display which is why I was hoping for further confirmation. That is what DavidR has just done so thanks for that and, of course, the earlier information from Avast-TS.