Already in Windows 10 as in the launch of Windows 11, both systems have had Windows Defender problems, which have varied greatly, after sending different versions of the system. For example, it has been reported that users have to manually activate the real-time protection of the antivirus every time the operating system is started. At the same time, another noted issue also refers to automatic sample submission being disabled after each PC reboot.
The first thing that we must take into account if we are facing problems with the operation of Windows Defender is that we have installed another antivirus. Although Windows allows you to install different antiviruses, it is not recommended without previously deactivating others, since, otherwise, both Windows Defender and the rest of the antivirus that we have installed will fight to analyze the files we download, the websites we visit, and so on. to protect us in real time. This means a high consumption of resources that, in the long run, harms the user experience. If we want to install an antivirus complementary to Windows Defender, we can do so, but we must deactivate the functions that overlap in one of them, that is, the functions that both can do to avoid loss of performance and high consumption of resources. If we install two devices we will not obtain greater protection as a team. If we want to complement Windows Defender, we must install an antivirus solution that does not offer the same functions as Microsoft’s native solution.
Generally, when we install an antivirus, Microsoft Defender is automatically deactivated, however, this is not always the case. If we have installed an antivirus and Windows Defender does not work, it is probably because it has been disabled. If we activate it without previously deactivating the one we have installed, we will face the performance problems that I have mentioned in the previous paragraph. But, if this is not the case, and we only use Microsoft Defender, we must find a solution to the problem through the steps that we show you in the following section.
Steps to solve the problem
If we have problems starting Windows Defender correctly in both Windows 10 and Windows 11, we can use the following actions to be able to solve it and be able to use our computer again as we did before.
Enable real-time protection
Windows Defender is an antivirus installed by default in Windows 10 and Windows 11 and is designed to go offline if another third-party antivirus is detected to avoid compatibility issues. Also, if the security software has a Firewall, the Windows Firewall will be disabled. This means that if we want Windows Defender to work, we must choose between it and another third-party antivirus.
There are times, especially when we buy a new computer, that it comes with a trial version of different antiviruses, such as McAffe, Norton, etc. In this case, if we have it enabled, we are disabling Windows Defender. Likewise, if we have installed any antivirus to test it, it can also cause the Windows security system to disconnect. That is why, when the time comes, we do not know if Windows Defender is activated or not, so if it is not, it may seem that it has a fault.
That is why we must reactivate it manually. This is something we can do quickly by typing Windows Security in the Start menu search box and selecting it. Next, we click Virus & other threat protection and Manage settings. On the next page we activate the section real time protection.
Update definition list
Windows, through Windows Update, is automatically responsible for downloading the updated files of all kinds of infectious software that circulates on the Internet. However, there is always the possibility that we have slipped in any type of software that is blocking not only the updated download of Defender definitions, but also that it may also be the culprit of Windows Defender not working. The solution to this problem is to manually download the list of Windows Defender definitions directly from the Microsoft page by clicking on the following .
Check system files with SFC and DISM
If Windows Defender fails, we can choose to perform a file system scan on the system to check if everything is correct or if there is a corrupt file that prevents it from starting correctly. To do this, we are going to use the SFC tool first and then the DISM tool.
The first thing will be to activate the Command Prompt for which we write cmd in the Start menu search box and run it with administrator rights. Later we write the following command and press Enter.
sfc /scannow
Once executed, we wait for the scan to complete, which can take time, so we must be patient. In case of finding a corrupt system file, this tool will repair it so we can verify if Windows Defender is damaged or not.
In case SFC is unable to fix the problem, we try to perform a scan with the DISM tool. To do this, from the Command Prompt window run as administrator, we enter the following command and press Enter.
DISM /Online /Cleanup-Image /restoreHealth
From this moment the scan will begin, which can take up to 20 minutes. Once finished we check if the problem persists, otherwise we go to the next solution.
Using Windows PowerShell
Another possible solution to this annoying Windows Defender problem is to use the PowerShell command line tool. For this we must write powershell in the Start menu search box and run it with administrator rights. Once the window appears, we must write the following command and press Enter:
Get-AppxPackage Microsoft.SecHealthUI -AllUsers | reset-appxpackage
Once this is done, it should solve the problem when opening the Windows antivirus, so we close PowerShell and restart the system to check it. If this is not the case, we move on to the next option to solve it. Although it may seem strange, the ability to update Windows Defender via PowerShell is available not for home users (who can also use it), but for companies to update all computers together with a single instruction without having to go team by team with the consequent loss of time that this entails.
Check Policy Editor Settings
Whether we have Windows 11 or the Pro and Enterprise versions of Windows 10, we can make changes to the system through the Local Group Policy Editor. If our computer is managed by the Home version of Windows 10 or Windows 11, this application is not available, so we must go to the next section to find a solution to the problem presented by Windows Defender. It is possible that Windows Defender does not work because we have made some modification here, so we must check that it is found correctly.
To do this, press the Windows + R keyboard shortcut to launch the Run command. here we write gpedit.msc and press Enter or the OK button. Once inside we navigate to the following route:
Computer Configuration / Administrative Template / Windows Components / Microsoft Defender Antivirus
Here we double click on the section Disable Microsoft Defender Antivirus.
In the new screen we mark the option of not configured and click Apply and OK to save the changes. We restart the PC and check if Windows Defender is already running correctly.
Check registry settings
It will also be necessary to verify that a registry modification has not been made where the use of Windows Defender has been disabled. This may have been caused by the installation of other antivirus software which, to avoid a conflict, disabled the Microsoft tool.
To do this, we will press the Windows + R keyboard shortcut to launch the Run command. Here, we type regedit and press Enter or the OK button. Once the registry is open, we must navigate to the following address:
HKEY_LOCAL_MACHINE/SOFTWARE/Policies/Microsoft/Windows Defender
Here we must locate the key DisableAntiSpyware. If it does not exist, we can create it by right-clicking on Windows Defender and selecting New and DWORD Value (32 bits) and giving it the name DisableAntiSpyware. We double click on it and set the value data to 0.
We close the Editor and restart the PC to check if Windows Defender is already running correctly.
update windows
It is important that we make sure that Windows is updated to the latest version available. With this, we not only make sure that the latest functions that are added are available, but also, in case of having an obsolete version, it can cause problems in Windows Defender, so an update can eliminate the error.
To do this, we simply have to open the Start menu search engine, write, Windows Update and select it. Once this is done, its section will appear in the Configuration menu. If we have updates available, click on the button Install Now. Otherwise we click Check for updates. Once the updates have been installed, it is recommended to restart the computer, even if it does not invite us to do so. This will start Windows fresh, and if the problem was related to updates, it should have been fixed.
Delete the last update
From we always recommend installing each and every one of the updates that Microsoft releases on the market. However, on certain occasions, the latest update can be a headache for our team and present stability and/or performance problems. Microsoft designs and maintains an operating system that is compatible with millions of computers with completely different configurations and components, unlike macOS, an operating system designed and updated every year to be compatible with just over a hundred computers, all of them with specific hardware. , so the problem of updates is reduced, which is not avoided, since, on more than one occasion, a macOS update has bricked millions of Macs.
Taking this aspect into account, if none of the options that we have shown you above solves the problem with Windows Defender, we should try to uninstall the last update that we installed on the computer in order to rule out that the update is the problem or continue looking for solutions. to the problem. For…