Thank you for being a valued part of the CNET community. As of December 1, 2020, the forums are in read-only format. In early 2021, CNET Forums will no longer be available. We are grateful for the participation and advice you have provided to one another over the years.

Thanks,

CNET Support

Resolved Question

Windows Defender error message.

Apr 25, 2017 8:44AM PDT

For some reason it has turned off and when I try and turn it on I receive the error message:

Windows cannot change some of your settings

Error code 0x8007042c

I have run SpyBot and Malwarebytes but neither have spotted any problems. How can I fix this?

Discussion is locked

8-bit has chosen the best answer to their question. View answer

Best Answer

- Collapse -
A Couple Of Possibilities.. But We Need More Information
Apr 25, 2017 10:13AM PDT

Computer make and model? Operating system used? EXACTLY how are you trying to turn it on?

And because this error is usually related to your Firewall, but could also be affecting Defender, it appears like you may be infected with malware. So... Please click on the link below and follow the steps EXACTLY in the order they're given..

“Expand” the post titled: "Please try this" at the link below:
http://www.cnet.com/forums/post/f742c795-5881-433b-a29b-6d758efe5cd3/

Hope this helps and let us know more.

- Collapse -
Thanks, heres my specs
Apr 25, 2017 12:49PM PDT

Thanks for the reply, will check that link out.

My PC is a custom build working from a GA-F2A88XM-DS2 motherboard. I'm running Win 8 and I'm going through the Control Panel/System and Security then Windows Firewall.

- Collapse -
Are You Also Running A Separate Antivirus Program?
Apr 25, 2017 1:03PM PDT

Many antivirus programs will automatically turn off Windows Defender so they don't conflict. As such, you would need to uninstall the other antivirus program before WD will work.

That said, if you're not running a separate antivirus program, instead of going through the firewall settings method, try turning Windows Defender on using the instructions in the link below:

https://answers.microsoft.com/en-us/windows/forum/windows_8-winapps/windows-defender-error-this-app-has-been-turned/86270742-a2a0-41db-9615-5471946e083b

Hope this helps.

Grif

- Collapse -
Anti virus software?....Yes
Apr 25, 2017 1:14PM PDT

Thanks.

I ran the Adware Cleaner but it didn't help. I AM running another antis virus program actually. I did not think Defender worked as a virus defender, I just assumed it stop another forms of attack. Will uninstall my antivirus software and see what happens.

- Collapse -
Anti virus software?
Apr 25, 2017 2:08PM PDT

So I uninstalled the two other system protective software I had and rebooted. I tried to turn on Defender but I still got the same message. Sad

- Collapse -
Which Other Antivirus Programs Were Installed?
Apr 25, 2017 2:56PM PDT

And running ADWCleaner is only PART of the fixes mentioned in my earlier link. It only finds adware and a few types of spyware. The other scanning tools are important.

And did you try turning on Windows Defender per my earlier instructions?

Grif

- Collapse -
All done, thanks!
Apr 26, 2017 12:09PM PDT

I went through all the steps, nearly 2000 adware type things were removed. I restarted my system and all was well. I would not have thought Adware would interfere with a Firewall installation!

Many thanks for your help and guidance. Happy

- Collapse -
Good Job ! That's Why Running ONE Antivirus Is Best
Apr 26, 2017 6:07PM PDT

When you have more than one AV program running realtime, they tend to conflict and don't find and eliminate malware as designed.

Hope this helps.

Grif

- Collapse -
Just one more thing.
Apr 27, 2017 7:32AM PDT

Just one more thing. If I have Defender running do I need a AV program at all? I assumed Defender was a Firewall and not an AV program?

- Collapse -
That's all I run
Apr 27, 2017 8:19AM PDT

Defender , to me is just fine !
It's the whole suite , anti virus , anti malware and firewall.
However , I do run malwarebytes occasionally but have only found tracking cookies..
I watch what sites I open as well as e-mails .
No matter which AV you choose, if you click on something or say yes,
you gave permission to bypass your AV and install a trojan or whatever . That is your fault , not the AV's

- Collapse -
Since You're Running Windows 8..
Apr 27, 2017 11:40AM PDT

The Windows 8 version of Windows Defender, which replaced Security Essentials, isn't quite as good at detecting viruses as its Windows 10 counterpart, but it's still decent. Yes, it is an antivirus/antimalware program and many choose to use only Windows Defender and not use anything else.

Just my opinion here, but although I've recommended users of Windows 10 to run Windows Defender only, I haven't done that with Windows 8. Instead, I disable Windows Defender and use a different antivirus such as the free versions of Avira or Avast. But remember, the most important "detector" of malware is YOU, the user. If you surf safe, running Windows Defender only is just fine. Here's a link that tells you about some of those issues:

http://www.pcworld.com/article/3025889/windows/tested-microsofts-windows-defender-antivirus-is-less-awful-than-it-used-to-be.html

Hope this helps.

Grif