diff --git a/src/win/win_sdl.c b/src/win/win_sdl.c
index bebad43dd..8a748fb2b 100644
--- a/src/win/win_sdl.c
+++ b/src/win/win_sdl.c
@@ -288,7 +288,8 @@ sdl_destroy_texture(void)
 void
 sdl_close(void)
 {
-    SDL_LockMutex(sdl_mutex);
+    if (sdl_mutex != NULL)
+	SDL_LockMutex(sdl_mutex);
 
     /* Unregister our renderer! */
     video_setblit(NULL);