diff --git a/common/TCPServer.cpp b/common/TCPServer.cpp
index cfba6e94a..2e3abfe2f 100644
--- a/common/TCPServer.cpp
+++ b/common/TCPServer.cpp
@@ -97,8 +97,12 @@ void BaseTCPServer::ListenNewConnections() {
 	from.sin_family = AF_INET;
 	fromlen = sizeof(from);
 	LockMutex lock(&MSock);
+#ifndef DARWIN // Corysia - On OSX, 0 is a valid fd.
 	if (!sock)
 		return;
+#else
+	if (sock == -1) return;
+#endif
 
 	// Check for pending connects
 #ifdef _WINDOWS