
So in case you want Windows Defender to work, then you will have to uninstall your third-party security software and reboot the system. Likewise, if this security application has a Firewall, then Windows Firewall will also stop working. So to avoid this situation, Windows Defender will turn itself off when it detects another security program. It often creates a conflict between them and in the end, it creates more trouble than doing any good. Frequent freezing, crashing to applications are some of the common issues which occur when you install more than one antivirus software. One of the common issues we have seen in the past is when there are multiple security software installed.

Windows is designed to detect the presence of security software installed, and we often get to see the notification in the Action Center. One of the most common behaviors of Windows Defender is that if it detects a third-party antivirus software, then Windows Defender will shut itself off.

If you face this issue, then this post may help you.Ĭan’t turn on Windows Defender in Windows 11/10

When I browse through forums I often find this question asked many times – I am unable to turn on Windows Defender manually or Windows Defender won’t or will not turn on and start in Windows 11, Windows 10, Windows 8, or Windows 7.
