SOLVED Fifty percent of my processor time stolen by unknown.

[Talisman]

Running Win10 at latest update level as of today KB4015217 and KB4013418.
I continually monitor processor percentage. I usually runs at 5-10% when doing nothing special. However now it runs at
45-50% when idling as shown by Task Manager. It moves up to 95% when accessing programs etc.
Problem is I cannot find what is using the processor time. The problem is way beyond my capabilities.
Task manager shows the culprit to be Antimalware Service Executable which includes Windows Defender which has a STOP option but it does nothing noticeable. Still 90-95%processor time used up.
So I visit system security and disable Defender which does not change the problem. So I rewake Defender for safety.
I do not have any other security or monitor programs installed.
I have downloaded and reloaded Win10 from scratch.
Its seems to me to be another security program but there is no other installed, I did try another program many moons ago but cannot remember which program.
Any constructive advice will be welcome.

 

[Data]

Talisman

That problem description is very little to go on, an actual process name and screenshots would be slightly better, but a capture of the actual problem with ScreenToGif for instance of Tasmanager and Resource monitor would probably be better.

e.g.

 

[Wolfie]

Hi, I had the same problem and solved it by opening System Settings > Network & Internet > Wifi and disabling the 3 buttons below the main Wifi switch (this is assuming that you are using Wifi?).

See image.

 

[Talisman]

Thanks both DATA and Wolfie. Could not change the situation no matter what I tried. Finally installed AVG anti virus which of course disabled Defender and Antimalware execthe problem is GONE!!!!..

 

[Wolfie]

Another thought, do you have several apps running at startup?, if you do, that may also be a reason why you have high CPU usage?, disable what you really don't need!.

 

[Data]

Well.... OK then, could have been some component of Defender, here I cant that issue.

Glad youre sorted.