Avg is not updating failed connection
To put it simply, this issue is possibly caused by the installation of third-party antivirus software, a corrupted registry, software conflicts, and so on.
For Windows 7, Windows 8 and Windows 10 users, it is fairly common.
Finally, restart your PC and try launching Windows Defender again to see if it can be turned on for virus, spyware and other threats protection.
In order to let Windows Defender work properly, you need to enable certain services.
Now, get Mini Tool Shadow Maker Trial Edition on your computer and then install it for file backup.
If you have installed any third-party software on your computer, Windows operating system will automatically detect it and turn itself down.It can offer real-time protection from various threats like spyware, malware, and viruses to your PC.Once it scans and finds potential threats, this program will stop them.Step 2: In the Command Prompt window, type sfc /scannow command line and press the Enter key. This process will take some time, so please wait patiently until verification reaches 100%.
Step 3: Later, exit the CMD window to check whether Windows Defender unexpected error is resolved.
Step 2: In the pop-up window, enter DISM /Online /Cleanup-Image /Restore Health and hit Enter to execute this command line.