diff --git a/gtk/chat.c b/gtk/chat.c
index c4fbffe36..79f0d0535 100644
--- a/gtk/chat.c
+++ b/gtk/chat.c
@@ -23,8 +23,8 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 #include <gtkosxapplication.h>
 #endif
 
-#ifdef WIN32
-#define F_OK 00
+#if defined(WIN32) && !defined(F_OK)
+#define F_OK 00 /*visual studio does not define F_OK*/
 #endif
 
 #define NB_MSG_HIST 250