diff --git a/v1/python.jam b/v1/python.jam
index 3a5dde1cd..36f2bcdf2 100644
--- a/v1/python.jam
+++ b/v1/python.jam
@@ -104,7 +104,7 @@ else if $(UNIX) && $(OS) = MACOSX
     PYTHON_ROOT = $(PYTHON_ROOT:J=" ") ;
     PYTHON_INCLUDES ?= $(PYTHON_ROOT)/include/python$(PYTHON_VERSION) ;
     PYTHON_FRAMEWORK ?= $(PYTHON_ROOT) ;
-    while $(PYTHON_FRAMEWORK:D=) != Python.framework
+    while $(PYTHON_FRAMEWORK:D=) && $(PYTHON_FRAMEWORK:D=) != Python.framework
     {
         PYTHON_FRAMEWORK = $(PYTHON_FRAMEWORK:D) ;
     }