We have decided to take an in-depth look into this problem since many people are going through it and don’t know how to solve it. Here is a shortlist that will help you understand what can cause this issue: Now that you are aware of all the possible causes for this error, here is a list of methods that will help you fix the Unknown error on Windows Defender, according to other affected users:
1. Disable any 3rd party antivirus (if applicable)
The first thing that you should do when you encounter this issue is to try to disable the 3rd party AV that you are currently using. This can be a helpful thing because the Unexpected error might be caused by the antivirus, which is not letting the Therefore, if you are currently using an antivirus program other than Windows Defender, you should consider temporarily turning it off to determine if that is the root of the problem. If the issue is resolved after turning off the third-party AV, you can uninstall it as well to ensure that it won’t happen again. Here is a guide with the step by step instructions on how to disable your 3rd party antivirus: In case the ‘Unknown error’ in Windows Defender still appears after disabling the 3rd party antivirus, go to the second method below.
2. Change the value of the DisableAntiSpyware value in Regedit
A lot of people that have managed to get rid of this error are recommending the to try to change the value data of the DisableAntiSpyware value. You can use the Registry Editor to change to value data. Authorized users can browse and modify the Windows registry using the Windows Registry Editor, a graphical application included with the Microsoft Windows operating system. Basically, you have access to every Windows, program, and driver value, as well as the ability to change them. You can do this by opening the Registry Editor and going inside the Windows Defender folder, there you should be able to see the DisableAntiSpyware DWORD Value. In case you don’t see it, you can create it, but you must change the value data to 0 in order to make this method work. Here is a guide that will show you exactly how to do this: In case the Unknown error still appears in Windows Defender, go to the next method below.
3. Run a full system scan with Microsoft Safety Scanner
Another thing that you can try is to do a full scan of your system using the Microsoft Safety Scanner. This process might actually fix your problem according to the people that have used it. The program called Microsoft Safety Scanner is made to discover and get rid of viruses on Windows systems. Simply download it, run a scan and look for malware to see if your system was affected by this. If there is malware found, that means the Windows Defender might not work because it was affected by this virus. In case you don’t know how to do this, here are the steps you need to follow: In case the Unknow error is still happening to your Windows Defender, go to the next method below.
4. Enable the Windows Firewall
It is worth trying to enable the Windows Firewall as well to see if this will fix your Windows Defender. Many affected users have confirmed that this method worked in their case. The Windows Firewall might be disabled, and this can be causing the Windows Defender to not work properly, so it is recommended you check the status of the Windows Firewall. All you have to do is to open the Control Panel and go to the System and Security section, where you will be able to select the Windows Firewall. There you will have to check and make sure that the Windows Firewall is enabled. Here are the steps that will show you how to enable the Windows Firewall: In case the Unknown error in Windows Defender is still present even after enabling the Windows Defender Firewall, go to try the next possible fix.
5. Run the Microsoft Defender Offline scan
Some other affected users have experienced this error and managed to fix it by running the Microsoft Defender Offline. This action is recommended to do if you are suspecting hidden malware on your computer but was also helpful for people that were trying to fix this Windows Defender error. Microsoft Defender Offline is an effective offline scanning tool that is being used when people are going through malware problems. To run the Microsoft Defender Offline scan, you have to go to the Virus & threat protection section inside the Windows Settings. There you will be able to select the Microsoft Defender Offline scan and start the process. Here are the steps that you will need in order to do a Microsft Defender Offline scan: In case the Unknown error still appears in Windows Defender even after trying all the methods before, go check the last one below.
6. Update your Windows
The last thing you should do is to make sure that you have the latest update for your Windows installed. If the Windows is outdated, this can cause many problems to the Windows, as well as the Unknown error. This can happen because the update is pending, waiting for you to install it. All you can do is go to the Windows Update to check if there are any updates uninstalled. If there are updates waiting to be installed, make sure to install all of them. The Windows Update can be found inside the Windows Settings of your computer. In case you don’t know how to check if your Windows is outdated, here are the exact steps you need to follow:
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