diff --git a/Source/CPack/cmCPackNSISGenerator.cxx b/Source/CPack/cmCPackNSISGenerator.cxx
index 1b547012b..470f5bc3d 100644
--- a/Source/CPack/cmCPackNSISGenerator.cxx
+++ b/Source/CPack/cmCPackNSISGenerator.cxx
@@ -147,7 +147,7 @@ int cmCPackNSISGenerator::InitializeInternal()
   if ( !cmsys::SystemTools::ReadRegistryValue(
       "HKEY_LOCAL_MACHINE\\SOFTWARE\\NSIS", nsisPath) )
     {
-    cmCPackLogger(cmCPackLog::LOG_ERROR, "Cannot find NSIS registry value"
+    cmCPackLogger(cmCPackLog::LOG_ERROR, "Cannot find NSIS registry value. This is usually caused by NSIS not being installed. Please install NSIS from http://nsis.sourceforge.org"
       << std::endl);
     return 0;
     }