diff --git a/core/network.h b/core/network.h
index 7c95d84d..127a55d1 100644
--- a/core/network.h
+++ b/core/network.h
@@ -31,8 +31,10 @@
 #include <time.h>
 
 #ifdef WIN32 /* Put win32 includes here */
+#ifndef WINVER
 //Windows XP
 #define WINVER 0x0501
+#endif
 #include <winsock2.h>
 #include <windows.h>
 #include <ws2tcpip.h>
diff --git a/testing/crypto_speed_test.c b/testing/crypto_speed_test.c
index 81be92c6..ba40722f 100644
--- a/testing/crypto_speed_test.c
+++ b/testing/crypto_speed_test.c
@@ -1,6 +1,9 @@
 // Hi-resolution timer
 #ifdef WIN32
-
+#ifndef WINVER
+//Windows XP
+#define WINVER 0x0501
+#endif
 #include <windows.h>
 double get_time()
 {