Windows Defender not working, no other AV installed?

[Dave M]

I have not installed any AV SW (that I know of) but my windows defender stopped working and says there is another AV running. How can I find out what is causing this and get defender back online? I have the windows home edition.

 

[Trouble]

Was this an upgrade install?
Do you remember, ever having any third party software security suites installed in the past, within the previous version of Windows?
Without some recollection it might be difficult to discover.
You could search the Programs and Features applet in the control panel and see if you can find any reference there.
You could also search through C:\Program Files and or C:\ Program Files (x86)
Maybe running something like AutoRuns from here might reveal something.
https://technet.microsoft.com/en-us/sysinternals/bb963902
There are so many possible programs Avast, Avira, AVG, Comodo, McAfee, Norton, Vipre (Sunbelt), Zone Alarm.... just to name a few.

 

[Alan Sh]

Reboot it again - mine needed doing twice after I removed Avast.