Or maybe you just don’t like Microsoft Defender and you want it gone from your PC. Or you may have run into an issue where Microsoft Defender is blocking the installation of a legitimate, safe app because it believes it is malicious so you need to temporarily disable it - it certainly wouldn’t be the first time someone has had this problem. If you’re looking to install a third-party antivirus app, Microsoft Defender may not be able to coexist with it and will need to be disabled. However, there are several reasons why you may want to disable it. Source: Shutterstock Why Turn off Microsoft Defender?įor a free anti-malware app, Microsoft Defender works pretty well.