diff --git a/src/d_clisrv.c b/src/d_clisrv.c
index b03eb478e..e26debd91 100644
--- a/src/d_clisrv.c
+++ b/src/d_clisrv.c
@@ -3235,7 +3235,7 @@ void D_QuitNetGame(void)
 			if (nodeingame[i])
 				HSendPacket(i, true, 0, 0);
 #ifdef MASTERSERVER
-		if (serverrunning && cv_advertise.value)
+		if (serverrunning && netgame && cv_advertise.value) // see mserv.c Online()
 			UnregisterServer();
 #endif
 	}
diff --git a/src/mserv.c b/src/mserv.c
index b9d1825eb..98dd0820b 100644
--- a/src/mserv.c
+++ b/src/mserv.c
@@ -434,7 +434,7 @@ void UnregisterServer(void)
 static boolean
 Online (void)
 {
-	return ( serverrunning && cv_advertise.value );
+	return ( serverrunning && netgame && cv_advertise.value );
 }
 
 static inline void SendPingToMasterServer(void)
@@ -532,7 +532,7 @@ Advertise_OnChange(void)
 
 	if (cv_advertise.value)
 	{
-		if (serverrunning)
+		if (serverrunning && netgame)
 		{
 			Lock_state();
 			{