Unauthorised change to windows (error 0xC004D401)

[silverwolfy]

This morning I woke up to find an unauthorised change to windows error, which then directed me to authenticate my version of windows on the microsoft website.
Unfortunately, the Windows Validation procedure kept on being interrupted.

After a lot of research, I eventually discovered that it was Avast that was causing the problem.
I had to completely uninstall Avast in safe mode to make the problem disappear.

From the posts over on the Microsoft forum, it looks like a lot of people are having similar issues (and the vast majority have Avast installed). Is anyone in the development team looking to solve this problem?
In the meantime, I've had no choice but to install a different AV program until the Avast compatibility issue is resolved. I've used Avast for quite some time now, and it has only occurred today, so maybe a recent update broke something?

When I am confident the issue has bee properly resolved, I'll be happy to reinstall Avast on my computer.

 

[CraigB]

You dont mention what version of windows you are using ? if your on vista it was a known issue with Vista SP1 but the latest 6.0.1203 is supposed to have fixed the problem.

[The Swami]

I'm getting the same error my system is windows vista 32 bit home premium and I've been using avast without any trouble until I reformatted my system 2 weeks ago. After my reformat I used the mcafee removal tool to remove my defalt AV and installed the latest Avast AV to my system then started up windows update and got this error. I reformatted again and repeated the same process but this time without any error and was able to bring windows vista up to date. I've had no problems until today when this error popped up again and just like Silverwolfy my research singles out avast as the problem. I <3 <3 <3 Avast and I hope a fix is available soon  :'(

[Asyn]

Guys, if you're on Vista...
1. Update your Vista to SP2..!
2. Update avast! to 6.0.1203..!

[silverwolfy]

Thanks, I'll try the Vista SP update. At the moment I'm temporarily using an alternative AV software until I'm confident the issue has been properly resolved.

The computer in question has Vista 64bit (OEM), and after checking it is indeed SP1, so I'll need to do the update.
Interestingly, the problem only occurred sometime after upgrading to the very latest version of Avast. I'm normally fairly prompt with that and install AV and anti-Malware updates as soon as I'm aware of them. With other software I tend to have an 'if it works, don't fix it' approach, unless there's some new function I really want.
Running the Diagnostics bought up two TTS tampers within 12 hours of each other - both of which I believe are associated with Avast.

Anyway, for now what I have is working. After the time I spent on fixing the problem yesterday (It took a while to figure out it was Avast) I see no reason to 'fix it' just yet.

[Asyn]

Thanks, I'll try the Vista SP update. At the moment I'm temporarily using an alternative AV software until I'm confident the issue has been properly resolved.

You're welcome..!
And yes, the issue has been fixed in version 6.0.1203