diff --git a/python/pyruntime.swg b/python/pyruntime.swg
index 02de816..52aaa16 100644
--- a/python/pyruntime.swg
+++ b/python/pyruntime.swg
@@ -7,7 +7,12 @@
 // Make sure our project, which uses the latter, doesn't trigger the
 // former since we don't want to debug python itself.
 // (http://old.nabble.com/problems-with-python24_d.lib-td4760095.html#a4760095)
+// Also, disable a check in MSVC when building for Multi-threaded Debug DLL
+// that complains about mix of headers with and without _DEBUG.
 #ifdef _DEBUG
+#if defined(_MSC_VER) && _MSC_VER >= 1400
+#define _CRT_NOFORCE_MANIFEST 1
+#endif
 #undef _DEBUG
 #include <Python.h>
 #define _DEBUG