diff --git a/unsupported/test/mpreal/mpreal.h b/unsupported/test/mpreal/mpreal.h
index c4f6cf0cb..9b96ec411 100644
--- a/unsupported/test/mpreal/mpreal.h
+++ b/unsupported/test/mpreal/mpreal.h
@@ -107,7 +107,7 @@
     #define MPREAL_HAVE_EXPLICIT_CONVERTERS
 #endif
 
-#define MPFR_USE_INTMAX_T   // Enable 64-bit integer types - should be defined before mpfr.h
+//#define MPFR_USE_INTMAX_T   // Enable 64-bit integer types - should be defined before mpfr.h
 
 #if defined(MPREAL_HAVE_MSVC_DEBUGVIEW) && defined(_MSC_VER) && defined(_DEBUG)
     #define MPREAL_MSVC_DEBUGVIEW_CODE     DebugView = toString();