diff --git a/CMakeLists.txt b/CMakeLists.txt
index e9d0b3d837..9a172ab9ea 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -345,7 +345,7 @@ if (WIN32)
     NumberToHex(${PROJECT_VERSION_MINOR} HEX_MINOR)
     NumberToHex(${PROJECT_VERSION_PATCH} HEX_PATCH)
     SET(CPACK_WIX_PRODUCT_GUID           "D9F136C1-3691-47E3-9079-4FE9C9${HEX_MAJOR}${HEX_MINOR}${HEX_PATCH}")
-    SET(CPACK_WIX_UPGRADE_GUID           "D9F136C1-3691-47E3-9079-4FE9C9${HEX_MAJOR}${HEX_MINOR}00")
+    SET(CPACK_WIX_UPGRADE_GUID           "D9F136C1-3691-47E3-9079-4FE9C9${HEX_MAJOR}0000")
 
     SET(CPACK_WIX_PRODUCT_ICON           ${CMAKE_CURRENT_SOURCE_DIR}/win32/res/clam.ico)
     SET(CPACK_WIX_UI_BANNER              ${CMAKE_CURRENT_SOURCE_DIR}/win32/wix_ui_banner.bmp)