Step 1: Install Massive X using the provided installer
Step 2: Go to "%COMMONPROGRAMFILES%\Native Instruments\Service Center\".
If there is no "NativeAccess.xml" there, copy included "NativeAccess.xml" into there.
If there is "NativeAccess.xml", check its size.
If its smaller than the included one, replace it with the included one.
Step 3: Register Massive X using the provied KeyGen.