diff --git a/dlls/mfreadwrite/tests/mfplat.c b/dlls/mfreadwrite/tests/mfplat.c
index 04d9590815e..06fed39aaa2 100644
--- a/dlls/mfreadwrite/tests/mfplat.c
+++ b/dlls/mfreadwrite/tests/mfplat.c
@@ -901,6 +901,7 @@ static void test_source_reader_from_media_source(void)
     LONGLONG timestamp;
     IMFAttributes *attributes;
     ULONG refcount;
+    PROPVARIANT pos;
     int i;
 
     source = create_test_source(3);