Windows 10: Maybe I accidentally allowed a threat

Had a Trojan horse detected by Windows Defender, went into the Protection History to solve it and get rid of it. Chose one of the actions not sure which one as I wanted to "delete" the virus from my PC once for all. Don´t remember which one tho. Is it possible that I allowed the virus to function and the PC doesn´t see it a threat anymore. PC seems fine, except sometimes in hidden icons the Defender icon is yellow. In that case Defender doesn´t open when I click on it. Neither does ist work when I try to access it through settings. After one or more restarts it gets green and is openable aga

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Windows defender false positive - forced to allow threat

Windows defender has started to identify C:\Windows\System32\mshta.exe as a threat [normally reported as a Trojan Powessere.G]. I use mshta.exe to run an hta custom MsgBox - I have been hoping to keep using my current CustomMsgBox tool [batch file calling a vbs-hta file] until later this year when I hope to have had enough time to replace it with a PowerShell alternative.

Windows defender's notification lets me "allow the threat" but that seems to me to be a bigger security hole than is necessary - it will now ignore a potentially real intrusion when all I want to run is a genuine Windows component. My immediate problem is fixed but I would prefer to fix the false positive using the exclusions list.

I cleared the 'Allowed threats history' so I could use the exclusions list instead. I added C:\Windows\System32\mshta.exe to the file exclusions list and I checked that it had taken properly by checking the exclusions list both in the UI & in the Registry. But the exclusion made no difference, it continued to detect and block the exe.

I have repeated the attempt several times [by clearing the allowed threats list & exclusions list beforehand] and the results are the same every time
- allowing the threat works,
- using the exclusions list has no effect.

I studied the relevant tutorial but have not spotted an error in what I have been doing - Add or Remove Windows Defender Exclusions

Does anybody with experience of using the exclusions list to counter false positives have any suggestions for me?

Denis

 

Is restoring a quarantined threat the same as allowing the threat?

My Windows defender scan reported a threat last week. I quarantined it. After a few days, I updated my defender virus definitions, restored the threat, and ran another scan (because I wanted to find out if it was a false positive). This new scan did not
report any threat.

However, under defender's threat history, allowed items, I see this threat listed. I do NOT want to allow the threat, just wanted to find out if the latest definitions would still reported the file as a threat. How should I do that? Thank you. I am using
windows 10.

 

Is restoring a quarantined threat the same as allowing the threat?

Thanks XP. My exclusion list is empty, and the only options on my threat history are "allow" and "clear history" (please see my screen shot above). How do I tell if I have whitelisted the threat please? Thanks.