Windows Defender, which is a part of Windows Security app, is the built-in anti-virus/anti-malware solution to protect your computer and data from unwanted viruses, ransomware, spyware, and other forms of online threats. Even though this sounds like a very good basic protection mechanism, there may times when you would want to disable Windows Security permanently (or temporarily).
Headsup: Starting with the Windows 10 May 2020 Update, Windows Defender Antivirus is known as Microsoft Defender Antivirus. But we still use the term Windows Defender Antivirus for the purpose of this guide.
I found myself in this situation when I was trying to extract the firmware of my phone using a tool (which is made by a reputable developer) that I had downloaded from github. This happens way too often when a particular tool/utility makes use of hack/loop-hole in the software to get the job done or if it contains signatures that remotely resembles some type of malware. I knew this tool was safe but Windows Defender/Windows Security wouldn’t let me use it.

This is one of the many reasons why one might want to disable Windows Security on their Windows 10 device.
Disable Windows Defender Antivirus using Windows Security
If you want to temporarily disable Windows Defender this might be the optimal solution you are looking for. You can disable Windows Defender right from the settings. Here’s how:
Step 1: Click Start.
Step 2: Search for Windows Security and click the same when it comes up.
Step 3: Click on Virus & threat protection.
Step 3: Click on the Manage settings option under the Virus threat and protection settings.

Step 5: Uncheck the Real-time protection toggle switch to disable the Windows Defender.

Once you complete the above step, the real-time virus check will be kept on hold until you turn in back on. For example, if you turned this option off if the Windows Defender wouldn’t let you install a particular software, you should be able to do so now.
Whenever you want to turn it back on, simply switch on the toggle switch on Step 5 and you should be good.
Disable Windows Defender Antivirus using Group Policy
The Windows Group Policy Editor helps to perform a variety of tasks when it comes to tweaking core Windows functions. The same can be used to disable Windows Defender too. But before that, we need to disable Windows 10 Tamper Protection feature in order to effectively edit Windows Group Policies.
Tamper Protection is a relatively new feature which was made available with the Windows 10 May 2019 update. The sole purpose of this feature is to prevent any potentially unauthorized changes to Windows Security that are not made through the UI (for example, through the Group Policy Editor). If you do not disable Tamper Protection, Windows Defender will automatically get enabled after a reboot.
Disable Tamper Protection
Follow the below steps to disable Tamper Protection on Windows 10:
Step 1: Click Start.
Step 2: Search for Windows Security and click the same when it comes up.
Step 3: Click on Virus & threat protection.
Step 3: Click on the Manage settings option under the Virus threat and protection settings.

Step 5: Click on the Tamper Protection toggle to turn it off.

Once the above steps are done, proceed to disable Windows Defender.
Disable Windows Defender
Follow the below steps to permanently disable Windows Defender:
Step 1. Click Start.
Step 2. Search for gpedit.msc and click on the top result to open the Group Policy Editor.
Step 3. Browse to the following path:
Computer Configuration > Administrative Templates > Windows Components > Windows Defender Antivirus
Step 4. Double-click the Turn off Windows Defender Antivirus policy.

Step 5: Click on the Enabled option to permanently disable Windows Defender Antivirus.

Step 6. Click on the Apply button and then click on the OK button.
Step 7. Restart your Windows.
If you even want to enable the Windows Defender back again, you can simply repeat the above steps and click on Not configured option in the Step 5.
You will notice that the “shield” icon still available in the taskbar. This is expected. Note that the icon is part of the Windows Security app, not from the Windows Defender Antivirus.
Disable Windows Defender Antivirus using Registry
There may be situations when you can’t access Group Policy Editor. For example, it is not available in some versions of Windows 10, or it could be disable by admin for you. If that is the case, you can use Windows Registry to disable Windows Defender Antivirus.
Disable Tamper Protection
Follow the below steps to disable Tamper Protection on Windows 10:
Step 1: Click Start.
Step 2: Search for Windows Security and click the same when it comes up.
Step 3: Click on Virus & threat protection.
Step 3: Click on the Manage settings option under the Virus threat and protection settings.

Step 5: Click on the Tamper Protection toggle to turn it off.

Once the above steps are done, proceed to disable Windows Defender.
Disable Windows Defender Antivirus from Registry
Editing the Registry can be risky, and it can cause potentially irreversible damages to your Windows installation if not done correctly. We recommend you do make a full backup of your device before proceeding.
Follow the below steps to disable Windows Defender Antivirus with Registry:
Step 1. Click on Start.
Step 2. Search for regedit and click on the first result from the search – Registry Editor.
Step 3. Browse to the following Path:
HKEY_LOCAL_MACHINESOFTWAREPoliciesMicrosoftWindows Defender
Step 4. On the left panel, right-click on the Windows Defender folder and select New, and click on DWORD (32-bit) Value.
Step 5. Name the key DisableAntiSpyware and create it.
Step 6. Double click on the newly created DisableAntiSpyware key and change the value from 0 to 1.
Step 7. Click on the OK button to save the changes.

Step 8. Restart your Windows device.
If you want to enable the Windows Defender Antivirus again, simply perform the above steps again and in step 5, simply right click on the DisableAntiSpyware key and delete it.