diff --git a/dlls/quartz/tests/filtergraph.c b/dlls/quartz/tests/filtergraph.c
index a82a6854e86..400f7a6d6ce 100644
--- a/dlls/quartz/tests/filtergraph.c
+++ b/dlls/quartz/tests/filtergraph.c
@@ -298,4 +298,5 @@ START_TEST(filtergraph)
     test_graph_builder_addfilter();
     test_mediacontrol();
     test_filter_graph2();
+    CoUninitialize();
 }
diff --git a/dlls/quartz/tests/memallocator.c b/dlls/quartz/tests/memallocator.c
index b0638e8cd6d..c5313f74dd4 100644
--- a/dlls/quartz/tests/memallocator.c
+++ b/dlls/quartz/tests/memallocator.c
@@ -87,4 +87,6 @@ START_TEST(memallocator)
     CoInitialize(NULL);
 
     CommitDecommitTest();
+
+    CoUninitialize();
 }
diff --git a/dlls/quartz/tests/misc.c b/dlls/quartz/tests/misc.c
index 720781438db..bd902a86700 100644
--- a/dlls/quartz/tests/misc.c
+++ b/dlls/quartz/tests/misc.c
@@ -173,4 +173,6 @@ START_TEST(misc)
 
     test_video_renderer_aggregations();
     test_filter_graph_aggregations();
+
+    CoUninitialize();
 }
diff --git a/dlls/quartz/tests/referenceclock.c b/dlls/quartz/tests/referenceclock.c
index a56fb2558ec..164fc3d89f8 100644
--- a/dlls/quartz/tests/referenceclock.c
+++ b/dlls/quartz/tests/referenceclock.c
@@ -110,4 +110,6 @@ START_TEST(referenceclock)
     CoInitialize(NULL);
 
     test_IReferenceClock_SystemClock();
+
+    CoUninitialize();
 }
diff --git a/dlls/quartz/tests/videorenderer.c b/dlls/quartz/tests/videorenderer.c
index d18620f5fde..3fa752294b3 100644
--- a/dlls/quartz/tests/videorenderer.c
+++ b/dlls/quartz/tests/videorenderer.c
@@ -160,4 +160,6 @@ START_TEST(videorenderer)
     test_basefilter();
 
     release_video_renderer();
+
+    CoUninitialize();
 }
diff --git a/dlls/shell32/tests/string.c b/dlls/shell32/tests/string.c
index c748f350e95..61fab0fcbba 100644
--- a/dlls/shell32/tests/string.c
+++ b/dlls/shell32/tests/string.c
@@ -110,4 +110,6 @@ START_TEST(string)
         else
             test_StrRetToStringNA();
     }
+
+    CoUninitialize();
 }
diff --git a/dlls/shlwapi/tests/string.c b/dlls/shlwapi/tests/string.c
index 0b4f28ba29e..79a645c2e71 100644
--- a/dlls/shlwapi/tests/string.c
+++ b/dlls/shlwapi/tests/string.c
@@ -957,4 +957,6 @@ START_TEST(string)
   test_SHAnsiToAnsi();
   test_SHUnicodeToUnicode();
   test_StrXXX_overflows();
+
+  CoUninitialize();
 }