Microsoft Defender vs. Norton Antivirus

About 20 minutes ago, I got a ping from Windows Security—got those periodic scans turned on—saying it flagged some threats sitting right inside my McAfee Total Protection folder.

Trojan.Obfuscator

The file's stuck in quarantine now, but I'm wondering if a virus actually managed to sneak its way into my antivirus directory, or if Microsoft Defender is just being totally paranoid.

Why would you even have two different antivirus programs running at the same time?
It’s actually pretty common knowledge that you should never, ever have two active AVs installed on one machine—it just causes nothing but trouble. You should probably just uninstall one of them...

Larry Ortiz5 said:Why on earth would you even have two antivirus programs running at once?
It’s pretty much common knowledge that you should never, ever have two different AVs installed on one machine... Just uninstall one already...

Microsoft Defender says I can run periodic scans while still using my main AV. I just turned those off though.