diff --git a/os/Xtranssock.c b/os/Xtranssock.c
index e32f58247..b761b3228 100644
--- a/os/Xtranssock.c
+++ b/os/Xtranssock.c
@@ -122,7 +122,6 @@ from the copyright holders.
 #define EADDRINUSE WSAEADDRINUSE
 #undef EWOULDBLOCK
 #define EWOULDBLOCK WSAEWOULDBLOCK
-#define EINPROGRESS WSAEINPROGRESS
 #undef EINTR
 #define EINTR WSAEINTR
 #define X_INCLUDE_NETDB_H