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Windows 11 Defender Not Working: 5 Ways to Fix it
6 min. read
Updated onOctober 4, 2023
updated onOctober 4, 2023
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A significant part of every Windows version, Microsoft Defender, has become one of the most reliable programs to protect your device against malware.
Built into Windows 11 as well, this program offers in-depth threat resistance research and advanced security to provide protection on all Windows devices.
So when an issue occurs and it doesn’t work properly or Windows 11 cannot open Windows Security, users turn to the Internet in search of causes and solutions to fix the error and get back the protection they need for their devices.
That is why we are going to take a look at the most common causes and show you how to get things on the right track.
How do I fix the Windows 11 Defender not working issue?
Before trying out more complicated solutions when your Windows Defender is not working, try out some of these quick fixes:
1. Change the date and time
2. Update Windows
3. Enable real-time protection
4. Run a SFC scan
5. Change the Proxy Server
If you change your mind and want to give a try to a third-party tool, chooseBitdefendersince it’s known for the high detection rates of the latest malware, along with unbeatable multi-layer ransomware protection.
This was our last solution for the Windows 11 Defender not working issue. Moreover, you can read more about the causes of this problem.
Why is my Windows Defender not working in Windows 11?
If you havethird-party antivirus softwareinstalled on your computer, note that it might lead to certain Windows Defender errors.
Choose to use either Windows Defender or a third-party antivirus tool. Also, if you just got a new laptop, check if it came with a preinstalled antivirus trial version as this can stop Windows Defender to work properly.
Here is what Microsoftsaidregarding the compatibility with other antivirus products:
What happens when another non-Microsoft antivirus/antimalware solution is used? Can you run Microsoft Defender Antivirus alongside another antivirus product? The answers depend on several factors, such as your operating system and whether you’re using Microsoft Defender for Endpoint (Defender for Endpoint) together with your antivirus protection.
And if you work with programs like Flash or Java, you might need to uninstall the free security scanner which can cause some issues.
Although this might come as a surprise, another common reason why Windows Defender might not start is an incorrect time and date as most system functions are dependent on time and date.
Even more, an outdated PC can lead to many errors so we always recommend you perform a full update on your computer and on the antivirus as well.
If you’re havingdifficulties updating Windows Defender, you might need to install the virus definitions manually.
Windows 11 cannot open Windows Security
Several users described a similar situation: when they click on theOpen Windows Securitybutton from theWindows Securitytab insideSettings, they see an unusual pop-up instead of actually opening the application.
It readsYou’ll need a new app to open this windowsdefender link, giving them the option to search the Microsoft Store for an app.
Fortunately, though, there is an easy solution to solve the problem right away. You simply need to press theWindowskey, typePowerShell, right-click it and selectRun as administrator, then copy-paste this command and pressEnter:Get-AppxPackage Microsoft.SecHealthUI -AllUsers | Reset-AppxPackage
Fore more info on what to do ifWindows Security is not opening on Windows 11, check out our dedicated guide.
What does Windows Defender has to offer to Windows 11 users?
Windows Defender is pretty much the same as it was on the previous OS but there is one remarkable feature called Microsoft Defender Application Guard (MDAG) that you should know more about.
It is available for several types of devices such as enterprise desktops and mobile laptops, as well as personally-owned laptops that are managed through Microsoft Intune or a similar tool.
Designed for Microsoft Edge and for Microsoft Office, themain purpose for Microsoft’s Application Guardis to prevent developing attacks and improve employee productivity:
Microsoft Defender Application Guard (Application Guard) is designed to help prevent old and newly emerging attacks to help keep employees productive. Using our unique hardware isolation approach, our goal is to destroy the playbook that attackers use by making current attack methods obsolete.
The way the system works is quite easy to understand. For example, for Microsoft Edge or Internet Explorer, MDAG will help isolate previously defined untrusted sites, therefore, protecting your company from any attack.
If someone opens a page from an untrusted website, Microsoft Edge will open the page in an isolated Hyper-V-enabled container.
You can choose which websites, cloud resources, or internal networks are to be trusted or not. Also worth mentioning is the fact that this feature doesn’t require Hyper-V to be turned on.
Now there you have it, the most likely situations that can create errors and the solutions to fix them on your Windows 11 device.
Moreover, if yourWindows Defender is turned offon your Windows 11 PC, do not hesitate to edit your registry in order to enable it back on.
And if theWindows Defender service won’t start, make sure to clean your registry and check your environment variables.
What solution from the ones presented above worked for you to fix the Windows 11 Defender not working issue? Let us know in the comments section below.
More about the topics:Windows 11,Windows Defender issues
Loredana Harsana
Windows Software Expert
Loredana is a passionate writer with a keen interest in PC software and technology. She started off writing about mobile phones back when Samsung Galaxy S II was on top of the world and she fell in love with tech of all sorts.
Whenever she’s not at her work desk, you’ll find her enjoying refreshing tea flavors, spilling stories on paper, and listening to the radio.
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Loredana Harsana
Windows Software Expert
Loredana is a tech enthusiast who tackles mobility, privacy, and networking in easy-to follow guides for everyone.
