Windows 10: Windows Defender will not activate

Perhaps a year ago, a friend paid someone to provide a new computer. It is some HP model that came with Windows 8.1 pre-installed. It possibly also came from HP with one of the big name (Norton, McAfee, or whoever) "security scan" application installed. A freeware antivirus application (Avast), along with a few other freeware items, were added before it was delivered to him. His data collection was copied onto the new hard drive and various programs he already owned (e.g. Word) were installed.

Today I offered to do the MS offered update to Windows 10 for him. Before beginning I uninstalled the security scan program and the Avast antivirus, wanting to just go with Windows Defender under Win10.

After considerable hurry up and wait, Windows 10 Home was in place and running. My last effort was to be to assure that Windows Defender was running. It wasn't; it isn't.

In Settings, on the Windows Defender tab, the controls are grayed out. At the very bottom is an active line saying something like
Use windows Defender
When I click on it I get a message box saying Windows Defender is inactivated. If I am using some other antivirus product, I should check its security settings. No other information is offered.

There is not another program that I can find. Programs and Features on the Control Panel lists nothing that could have antivirus or other security functions. I suspect that some registry setting from one of the two now uninstalled programs caused Windows Defender to inactivate. A registry value to that effect was carried forward into the Widows 10 installation.

Unfortunately I don't know how to go about finding this, nor what to do about it. Is there some turn-on-Defender override that is hidden outside the normal settings? How can I get Windows Defender to wake up and take notice?

:)

 

windows defender will not activate in my windows 10 gives Error code: 0x800b0003

windows defender will not activate in my windows 10 gives Error code: 0x800b0003

 

windows defender will not activate in my windows 10 gives Error code: 0x800b0003

What operating system did you upgrade from?

What was the installed antivirus program on your PC prior to the upgrade?

Was there ever any other antivirus program installed, even a trial and how were they/was it removed?



A possible reason for this problem is that you have conflicting security software installed fully or partially on the PC. Remove all other security software from the PC.

You may need to use a cleanup tool to remove your prior security software. See this Wiki article:
List of anti-malware product removal tools



See
Problems starting Windows Defender in Windows 8/8.1/10



Consider -

Restore, reset, refresh Windows:
http://windows.microsoft.com/en-US/windows-8/restore-refresh-reset-pc or

How to Reset your Windows 10 Operating System

 

You could try the avast uninstaller from here to make sure it is fully uninstalled Avast FAQ | Avast 2015: Using the Uninstall Utility

 

Another option would be to reinstall Avast and uninstall it again. This would modify the registry automatically to enable Windows Defender when Avast is uninstalled. I think a better option to Windows Defender is Windows Security Essentials, but I don't know if there is a Windows 10 version yet or even if Windows Defender in Windows 10 is as good as Security Essentials so the latter isn't necessary.

I read of how to disable Windows Defender. It involved a registry key, but I cannot find that right now. Search this forum to find the thread. Set the key as appropriate to enable it back.

 

Microsoft Security Essentials (not Windows Security Essentials) will not run on Windows 8, 8.1 or 10 as the built-in Windows Defender is Microsoft Security Essentials as far as capability is concerned.

 

Yes, I thought so. Never tried installing it on Windows 8, I usually install another free antivirus such as Avast or AVG Free.