In your Windows 10 OS, you get so many features or services. These services will help you to complete various technical tasks very easily. But sometimes you also get some error issues in the computer if there any problem. Microsoft provides Windows defender program in the Windows 10 OS. It is used to scan and fix the infection issues properly. But sometimes when you try to launch the Windows defender program in the computer, you may get Windows defender error 15100. Defender error code 15100 may come to you due to corruption of the system files associated with this program. In this case, you should apply the manual or automatic error fixing methods. You can download and install Advanced System Repair Tool for automatic fixing of the issue.