Windows 10: severe threat detected

I'm getting a severe virus threat that continually is trying to load. Defender cleaned most of them except this one:


What should I do about this?

:)

 

Severe threat detected

I need help I do not know what to do next can someone please help me Windows Defender found a severe threat I send file to Windows Defender team for evaluating, and I got a message today said it is a Severe threat ::::: ( Backdoor:Win32/Floxif ) the
Alert Level Status is SEVERE to remove it immediately, But I have know clue how to do this and make my computer safe please help me

 

PUP Threats Detected By Malwarebytes

Check your list of installed programs and remove any toolbars. Run MBAM again, including rootkit detection, and do a full scan of all your hard drives, not just a Threat scan. Then, reset your Chrome browser.

 

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