Went to scan a file with the built in Win 10 scanner. It came up and said the file was excluded from scan. So it gave me a link to the exclusion directories of the virus scanner. I looked and it had the entire C drive as the last exclusion. I did not do this. I have specific directories on exclusion, but not the entire drive.

I got rid of this exclusion and scanned the entire drive. I didn't get any virus or worm hits.

Is this a sign of an infection?

It would have had to be changed with something that asked for permission to make administrative changes like an install. I honestly don't know what I would have installed that I gave permission to do this lately.

Is there a way to accidentally right click somehow to add a directory to the exclusion list?