Microsoft includes its own security suite with Windows, in the form of Windows Defender. It’s a decent option in many cases, and usually gets out of the way if you install another antivirus package.
Should you wish to disable it completely, then you’ll need to follow our guide below. It's unwise to have no security software though, as we discuss in Do you need Antivirus on a new Windows PC or laptop?
Back up your system first
Before you start making changes to the Registry in Windows, it’s essential that you make a backup of your system. While disabling Windows Defender is straightforward and safe, as you’ll be interacting with the structural elements of your PC’s operating system it’s always wise to ensure that you have an up-to-date backup to hand.
This is mainly just for peace of mind, but also provides you the ability to restore your machine to its current state should any of the commands be mistyped or disaster strikes.
How do I disable Defender temporarily?
If all you’re looking to do is turn off Windows Defender for a short while, then that is easy to achieve with our separate guide: How to turn off Windows Defender.
Permanently disabling Windows Defender
To access the settings where you’ll be able to disable Windows Defender, you’ll need to use the Run command.
Do this by holding down the Windows key and tapping on R. You’ll see a small window entitled Run appears. In the text field type regedit and click OK.
Next you’ll see a new window entitled Registry Editor, with a column on the left side which includes a file tree. Use this to navigate to the following folder;
There should be one file in the folder, named (Default). To disable Windows Defender you’ll need to add another. So, right click on an empty part of the pane, then select New>DWORD (32-Bit) Value.
Call the file DisableAntiSpyware, being sure to use the capitalisations as we've written it.
Right-click on the new file then select Modify. In the field marked Value data enter the figure 1 and click OK.
Now Windows Defender will be disabled. If you decide you want to reverse this decision then return to the DisableAntiSpyware file and set the Value data to 0.
Don't forget to install some antivirus software in place of Defender: it isn't a good idea to leave your machine with no protection.