diff --git a/os/connection.c b/os/connection.c
index d975f87..4b04f2f 100644
--- a/os/connection.c
+++ b/os/connection.c
@@ -1068,9 +1068,11 @@ AddEnabledDevice(int fd)
 _X_EXPORT void
 RemoveGeneralSocket(int fd)
 {
-    FD_CLR(fd, &AllSockets);
-    if (GrabInProgress)
-	FD_CLR(fd, &SavedAllSockets);
+    if (fd != -1) {
+	FD_CLR(fd, &AllSockets);
+	if (GrabInProgress)
+	    FD_CLR(fd, &SavedAllSockets);
+    }
 }
 
 _X_EXPORT void