diff --git a/var/spack/repos/builtin/packages/mumps/package.py b/var/spack/repos/builtin/packages/mumps/package.py
index 5c120c37df8..5a254dfd00e 100644
--- a/var/spack/repos/builtin/packages/mumps/package.py
+++ b/var/spack/repos/builtin/packages/mumps/package.py
@@ -135,7 +135,8 @@ def install(self, spec, prefix):
 
         self.write_makefile_inc()
 
-        make(*make_libs)
+        # Build fails in parallel, at least on OS-X
+        make(*make_libs, parallel=False)
 
         install_tree('lib', prefix.lib)
         install_tree('include', prefix.include)