In the Windows operating system, you will see some amazing features that lead you to a new height of technology. You usually use an antivirus tool to scan and fix the computer virus. But in Windows 10 OS, you get Windows defender program. This program will find out the infections and fix them soon. However, you may also get some error issues while you run the Windows defender. Windows defender error 0x6D9 is also one of them. The issue will harm the computer data very much and make you unable to scan the computer using any program. In this situation, you must go with some manual or automatic error fixing methods. For automatic fixing of the error, you can download and install Advanced System Repair Tool.