Since it’s a built-in program, you might be thinking that disabling Windows 10 Defender will cause harm to your PC. This is not the case. As we’ve already established, you can’t actually delete it completely. You can merely turn it off, which is completely harmless. That being said, there are a few things that can go wrong when trying to permanently disable Windows 10 Defender. Especially when you’re using Registry. However, you just need to be careful about following the required steps and back up important files. It’s also not a good idea to disable Windows 10 Defender without downloading a different, third-party antivirus program. As lackluster as you may view it, Windows 10 Defender still acts as a decent anti-malware protection.