Windows Defender turns off and will not turn back on

[Dolk]

Hey guys, I have an odd issue going on with my home system. I noticed that Windows Defender real protection was disabling on its own, and than would not turn back on with manual enable. I installed Malware-bytes and scanned my system: nothing. A few days later, Malware-bytes could no longer enable its web real-time protection service. Again same issue, forced enable would do nothing. So I uninstalled it and got a 30day free trial of Norton delux and did a scan. It didn't find much, and so far seems to be working just fine for right now.

Anyone ever run into this situation before? It sounds like I have a pretty nasty worm growing in my system.

 

[EarthDog]

I'd agree with the last part. If multiple AV apps are exhibiting the same behavior, I'd venture a guess as well you are infected.

SOunds like a good time for a fresh install.

 

[ATMINSIDE]

Safe mode, no networking, run Malwarebytes. If it won't run at that point, nuke the OS.

 

[Dolk]

Yeah all safe-mode scans have yielded no viruses. Just the standard cookies.

 

[Kenrou]

You realize most people would consider your problem as a good thing [emoji23]

 

[habbajabba]

Time to use backups. I use Veeam Agent for windows 'cause reinstalling is a major pita. BTW, so much for defender eh?
Sysinternals autoruns should be able to pinpoint the culprit/s however. These types of things always run at boot.

 

[mackerel]

If it is something that is not physically impractical, I'd get a 2nd known clean system, fully updated with AV etc. Put the suspect OS drive on that as a secondary, and use that system to scan.

 

[trents]

Have you tried a boot time scanner like that offered by Bitdefender?

 

[Alaric]

If it is something that is not physically impractical, I'd get a 2nd known clean system, fully updated with AV etc. Put the suspect OS drive on that as a secondary, and use that system to scan.

Now that's a good idea. I'll have to remember that.

 

[Dolk]

I ended up reformating my main drive and fresh installing Windows for safe measures. It was defintley a very secretive virus that didn't want to come out.

 

[ratbuddy]

Now would be a splendid time to change any important passwords, chances are someone nabbed them all.

 

[ADominus]

The behavior you are describing may occur if a third party program is installed or there are remnants of a third party program installed.

Go to Security and Maintenance, look in 'Security' and see what program is listed under Virus Protection. Windows Defender will not be enabled if there is a program other than Windows Defender listed.

Have you tried the steps recommended in Problems starting Windows Defender in Windows 8/8.1/10 to include running the software removal tools for any security software (AVG, McAfee, Norton, whatever) that may have previously been on the computer followed by a reboot?

I used WD and had no complaints regarding the program. But You may prefer to install a third party antimalware program (which should disable Windows Defender) and you’ll no longer be concerned with the various issues that intermittently affect Windows Defender on Win 10.