Windows defender program is a very dynamic and amazing program that comes to you with the upgrading of your operating system to Windows OS 10. The program acts just like an antivirus. It scans and find out errors and tries to repair them properly. But sometimes while you launch the Windows defender program in your computer, you get Windows defender error 0x80508018. Occurring of the defender error code 0x80508018 is a very critical error issue and you need to fix it as soon as possible. Here it is to be noted that there are no any proper causes or reasons for the occurring of this issue. But it is assumed that the issue comes due to deletion or missing of Windows system files associated with this program. So, go with the methods recommended here to fix Windows error code 0x80508018. For automatic fixing, you must download and install Advanced System Repair Tool in the computer.