Windows operating system comes with many features that are very much important for completing your personal or professional works. You can access your computer very easily by using these features. But sometimes the features itself give you some very critical errors that are hazardous for the health of the computer. DNSAPI.dll is missing error in Windows is also such types of error that comes to you due to the corruption or the missing of the DNSAPI.dll file. Actually this DLL file is responsible for the proper running of the applications associated with it. So when the file gets corrupt, you may have this error issue. It is a very critical error and it should be fixed as soon as possible. You can resolve this problem with the help of the manual or automatic methods. For automatic troubleshooting, you can download and install Advanced System Repair tool in your computer.