diff --git a/Modules/Platform/Darwin-Initialize.cmake b/Modules/Platform/Darwin-Initialize.cmake
index 91c2cf3c4..427909d6c 100644
--- a/Modules/Platform/Darwin-Initialize.cmake
+++ b/Modules/Platform/Darwin-Initialize.cmake
@@ -125,8 +125,10 @@ if(CMAKE_OSX_SYSROOT)
       set(_CMAKE_OSX_SYSROOT_ORIG "")
     endif()
     set(_CMAKE_OSX_SYSROOT_PATH "${CMAKE_OSX_SYSROOT}")
-  else()
-    # Transform the sdk name into a path.
+  endif()
+
+  if(CMAKE_OSX_SYSROOT)
+    # Transform the (maybe unversioned) sysroot into a versioned path.
     execute_process(
       COMMAND xcodebuild -sdk ${CMAKE_OSX_SYSROOT} -version Path
       OUTPUT_VARIABLE _stdout