The post instructs students and new users on enabling Microsoft Defender, a free anti-malware feature of Windows 11. Steps are provided to access the System Settings, and specific ways to activate Microsoft Defender for different network profiles. Though Microsoft Defender can run alongside other security programs, it can be turned off if it causes interference. The post emphasizes keeping the default security software enabled for optimal protection.
This post shows students and new users how to turn or enable Microsoft Defender (previously known as Windows Defender) on or off when using Windows 11.
Microsoft Defender (previously known as Windows Defender) is also included in the new Windows 11, part of Microsoft Security. Microsoft Defender is free anti-malware software in Windows 11 to help you stop viruses and malware from installing on your computer.
Microsoft Defender should be a great feature to turn on and use if you don’t have other commercial antivirus or security programs installed. For some, Microsoft Defender is still used even with other third-party security programs installed on Windows 11.
Windows Defender helps protect your computer from authorized access and adds another layer of security in protecting your data and identity from bad actors.
How to Enable Microsoft Defender
Below are steps that help you turn on or enable Microsoft Defender if it’s disabled:
Windows 11 has a centralized location for the majority of its settings. Everything can be done, from system configurations to creating new users and updating Windows from its System Settings pane.
To get to System Settings, you can use the Windows key + I shortcut or click on Start ==> Settings, as shown in the image below:

Alternatively, you can use the search box on the taskbar and search for Settings. Then select to open it.
Windows Settings pane should look similar to the image below. In Windows Settings, click Privacy & security, and select Windows Security on the right pane of your screen shown in the image below.

On the Windows Security setting pane, click the “Open Windows Security” button as highlighted below,

That will bring you to the Windows Security home settings pane. From the left menu items, go to Firewall & network protection.
There you will see up to three network profiles.
- Domain network: Network at workplace that are joined to a domain. This is mostly found in business environments
- Private network: Network are home or work where you know you trust the devices in your network and where device are set to be discovered via network discovery.
- Public network: Network in public areas such as airports, coffee shops, and others where devices are not configured to be discovered.
You can go into each network profile above and turn on or turn off the Microsoft Defender firewall for each.

Select a network profile, and turn it on or enable it if it is already disabled.

If the profile is enabled, you can disable or turn it off.

Next, go to Virus & threat protection on the left menu; under Virus & threat protection on the right pane, click the Manage settings link.
Then enable or turn Real-time protection and Cloud-delivered protection. If enabled, you can then disable or turn it off.

App & browser control can also be turned off or disabled.

By all means, Microsoft Defender should be enabled and receive updates on your Windows computer. The only reason you may want to turn it off is when you have other security products installed, and Microsoft Defender is interfering with them.
If Microsoft Defender is not impacting your PC performance or interfering with other security suites installed, you should keep both installed and enabled.
Conclusion:
This post showed you how to enable Microsoft Defender in Windows 11. If you find any error above, please use the comment form below to report.
I get an error saying: “You will need a new app to open this windowsdefender link”. All my options are to open the Microsoft Store which does not give any other options after all.
I have same issue, and i am still searching solution. I found one more thing Windows defender service is stopped and it is not getting started.
Hi .. I can’t open Windows Sercurity .. it doesn’t run any progress … and I don’t see protection arena like pic.2
i have the same problem i can’t open the windows security
This this post.
Enable the service 🙂
Service.msc in the search bar
Find the windows Defender process and enable is click on start and that problem is gone.
Not true. Mine starts and stops immediately thereafter. An sfc /scannow shows no issues. I also have Malwarebytes installed and I know it likes to disable Windows Defender but that should not stop me from enabling it again.
Windows Defender and Windows Update not working in Windows 11 LITE