You start Microsoft Windows Defender on your computer. After you do this, you use Add or Remove Programs in Control Panel to try to remove Windows Defender. However, you receive an incorrect message that resembles the following:
The following applications should be closed before continuing the install:
When you click Retry in the message dialog box, you receive the same message.
This problem occurs because there is one instance of Windows Defender that is running on the computer. Therefore, some Windows Defender files are currently open and cannot be deleted.
To resolve this problem, use one of the following methods:
Close the instance of Windows Defender that is running on the computer, and then remove Windows Defender.
Restart the computer, and then remove Windows Defender.