Microsoft acknowledged the growing threat of spyware with the launch of Windows Defender a few years ago. It’s available for Windows XP through to Windows 7. In Windows 8, Microsoft provided an enhanced version of Defender which also protects against malware – effectively rolling Security Essentials (Microsoft’s free antivirus program) and Defender into one. It's the same in Windows 10. Here's how to turn on or off Windows Defender in Windows 10, Windows 8, 7, Vista and XP.

The revamped Windows Defender rubbed all the security software companies up the wrong way, so Microsoft provided an option to turn off Defender when a trial version of a security suite was installed on a new PC or laptop. This is because the two will probably conflict with each other and cause performance problems.

However, if you don't activate that McAfee or Norton trial, Defender won’t automatically enable itself again, so you’re left unprotected from malware. And that's not a good thing. However, rather than using Defender, there are better free antivirus programs you can install - see the 6 best free antivirus software for more.

How to check if Windows Defender is running

It’s easy enough: simply look for its icon in the Notification area (the space to the left of the clock to the right of the Taskbar). It might be in the list of hidden icons, so click the little upward-pointing arrow and look for a castle icon.

Don’t worry if you can’t find it – it may still be running, or your computer might already be running other security software which is doing a similar job.

If you’re still not sure or you know your computer definitely doesn’t have an antivirus program or security suite and you don't want to install one, here’s how to enable Windows Defender.

How to turn on or off Windows Defender

Step 1: In the Start menu (or on Windows 8’s start screen) type Defender. Windows Defender should appear in the list. Click on it to launch the program. If it’s already running, and you see the main window, skip to step 5.

How to turn on or off Windows Defender in Windows 10, 8, 7, Vista, XP

Step 2: You might see a message like the one below, showing that Defender is turned off and isn’t protecting your computer. If so, search for Action Center in the Start menu (or screen if using Windows 8) and run that.

How to turn on or off Windows Defender in Windows 10, 8, 7, Vista, XP

Step 3: In Action Center, click on the Security tab to check which program is handling spyware and unwanted software protection. If you want to enable Defender in place of another suite such as McAfee, you should use the Control Panel to uninstall that first.

Windows 8 Action Center

In Windows 10, Microsoft has moved things around a little, so you need to open the Control Panel (not the Settings app), and go to System and Security > Security and Maintenance. Here you can see that AVG Free Edition is installed, and is the reason why Windows Defender is turned off. Again, you will need to uninstall any such software if you want to use Windows Defender instead.

How to turn on or off Windows Defender in Windows 10, 8, 7, Vista, XP

Step 4: When you have uninstalled any antivirus or antispyware, type Defender again in the Start menu and, if it’s turned off, you’ll see a message and a link to turn it on. Click it to turn on Windows Defender.

Windows Defender click here to turn on

Step 5: Assuming your computer isn’t protected, the Windows Defender main window will open on the desktop. It's likely that the spyware definitions will be out of date, so now’s the time to update them. Click the Check for Updates button. Here's what it looks like in Windows 7:

Windows Defender (Win 7) update

Step 6: When updates are downloaded, you should see a nice green bar showing that Defender is up to date and protecting your computer.

Windows Defender up to date

In Windows 10 it looks like this:

How to turn on or off Windows Defender in Windows 10, 8, 7, Vista, XP

Step 7: Click the Tools link at the top and then on Real-time protection in the left pane. Check that it’s enabled and then choose options for scanning downloads, attachments and programs that run on the computer. We advise enabling all the options here.

Windows Defender real-time protection

In Windows 10, the settings are - confusingly - also found in the Settings app under Update and Security:

How to turn on or off Windows Defender in Windows 10, 8, 7, Vista, XP

If you turn off Windows Defender in Windows 10 using the toggle buttons above, bear in mind that it's a temporary thing. Protection will be re-enabled to keep your PC secure. Note that the buttons are greyed out in the image above because third-party antivirus software was installed on our test laptop. You will only be able to use these controls if you uninstall the other antivirus software first.

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