Defender Antivirus – CompTIA A+ 220-1102 – 2.5

Microsoft Defender Antivirus is included with Windows by default, and it’s important to know how to manage this service when troubleshooting. In this video, you’ll learn about activating, deactivating, and updating the virus definitions in Microsoft Defender Antivirus.


If you’re running Windows 10 or Windows 11, you have some antivirus and anti-malware software that’s already built into your operating system called the Microsoft Defender Antivirus. This is included with Windows so you don’t have to purchase antivirus from a third party, and you don’t have to pay for yearly updates. This is in the security app of Windows 10 and Windows 11, and it provides protection against viruses and malware.

You may find other references to this utility as Windows Defender. But these days the name is Microsoft Defender Antivirus. Your antivirus software should always be enabled and it should always be configured for real time analysis. This means that when you download a file or launch an application, your antivirus software will examine that code and will determine whether it’s malicious or not.

However, there may be times when you’re troubleshooting an application and the application developer asks you to temporarily disable the real time access to see if that’s what’s causing the issue. Microsoft Defender Antivirus allows you to enable and disable this real time protection. And you can find this in the Windows Security app under virus and threat protection settings, , manage settings and real time protection.

Let’s try this on my Windows 11 machine. I’m going to click the Search option and just type in security. That will bring up the Windows Security app as the best match inside the Windows Security app. It’s an option for virus and threat protection. And inside, there will tell us that there are no current threats and when the last scan occurred. Inside of this is an option for virus and threat protection settings with a link to manage settings.

Inside the managed settings, we can enable or disable real time protection, change the cloud deliver protection option, and change the automatic sample submission option. To disable the real time protection, we’ll simply click the option to turn that off. At this point, Windows will give you a user account control dialog box, which should give you an idea that what you’re about to do is relatively significant.

It says, do you want to allow this app to make changes to your device? This would be for the Windows Security. And in this case, yes, we would like to disable that real time protection. Once you do that, the virus and threat protection settings will tell you that real time protection is off and Windows Security puts a message on your screen telling you that you should probably turn on the virus protection. Once you’ve finished troubleshooting your application, you can turn the real time protection back on and your system is back to running normally.

Your antivirus application is able to determine whether software is malicious or not based on a series of signatures that are installed inside of the antivirus program. To be able to maintain the best security for your system, you’ll need to make sure that these signatures are always up to date. This is something that can be done automatically from inside of Microsoft Defender Antivirus, or you can manually have it check for these updates.

Most of the time, you’ll never have to perform a manual update. But there may be times during a troubleshooting process where having the latest signatures may be able to resolve problems with an application performing properly. Let’s run a manual update on my Windows 11 machine. I’ll click the search. We’ll type in security and choose the best match of the Windows Security app. Inside this app, we’ll choose the option for virus and threat protection.

And near the bottom of this screen are the virus and threat protection updates. It tells us that security intelligence is up to date. But let’s perform a manual update anyway. I’m going to click the option for protection updates and it has a link inside of it that tells me that I can check for updates. It then goes out to the Microsoft Cloud, brings down any updates for this system, and then make sure that everything is up to date with the latest version.

If you’re having problems with an existing set of antivirus signatures or you want to be sure that you’re always using the latest set when you’re troubleshooting, you may want to perform one of these manual updates.