As you know that the Windows defender is an inbuilt security tool of the Windows computer. It scans the whole computer and tries to remove infectious files from the system time to time. However, sometimes when you try to run this tool in the computer, you get Windows defender error 0x80508020 on the computer screen. After getting the defender error code 0x80508020 in Windows, you cannot be able to remove the threats and infectious if you have not installed any third party antivirus. In this case, it is very important to remove this problem as soon as possible. Hence, you should first go through the manual or automatic error fixing methods given here. For automatic fixing, you can download Advanced System Repair tool in the computer.