diff --git a/lib/spack/spack/platforms/darwin.py b/lib/spack/spack/platforms/darwin.py
index cfa1d957a1..5b797a78db 100644
--- a/lib/spack/spack/platforms/darwin.py
+++ b/lib/spack/spack/platforms/darwin.py
@@ -1,5 +1,6 @@
 import subprocess
 from spack.architecture import Platform, Target
+from spack.operating_system.mac_osx import MacOSX
 
 class Darwin(Platform):
     priority    = 89
@@ -10,7 +11,9 @@ class Darwin(Platform):
     def __init__(self):
         super(Darwin, self).__init__('darwin')
         self.add_target(self.default, Target(self.default, 'PATH'))
-        self.add_operating_system()
+        mac_os = MacOSX()
+        self.default_os = mac_os.name
+        self.add_operating_system(mac_os.name, mac_os)
 
     @classmethod
     def detect(self):