diff --git a/dlls/winmm/mciavi/mmoutput.c b/dlls/winmm/mciavi/mmoutput.c
index 107c0661e44..df4e2140ad4 100644
--- a/dlls/winmm/mciavi/mmoutput.c
+++ b/dlls/winmm/mciavi/mmoutput.c
@@ -604,7 +604,5 @@ LRESULT MCIAVI_DrawFrame(WINE_MCIAVI* wma)
        ReleaseDC(wma->hWndPaint, hDC);
     }
 
-    LeaveCriticalSection(&wma->cs);
-
     return TRUE;
 }