diff --git a/dlls/comctl32/tests/comboex.c b/dlls/comctl32/tests/comboex.c
index eca7ca4..7fe0874 100644
--- a/dlls/comctl32/tests/comboex.c
+++ b/dlls/comctl32/tests/comboex.c
@@ -339,6 +339,8 @@ static void cleanup(void)
 
 START_TEST(comboex)
 {
+    winetest_exclusive();
+
     if (!init())
         return;
 
diff --git a/dlls/comctl32/tests/datetime.c b/dlls/comctl32/tests/datetime.c
index b194cc1..5bff228 100644
--- a/dlls/comctl32/tests/datetime.c
+++ b/dlls/comctl32/tests/datetime.c
@@ -579,6 +579,8 @@ START_TEST(datetime)
     BOOL (WINAPI *pInitCommonControlsEx)(const INITCOMMONCONTROLSEX*);
     INITCOMMONCONTROLSEX iccex;
 
+    winetest_exclusive();
+
     hComctl32 = GetModuleHandleA("comctl32.dll");
     pInitCommonControlsEx = (void*)GetProcAddress(hComctl32, "InitCommonControlsEx");
     if (!pInitCommonControlsEx)
diff --git a/dlls/comctl32/tests/header.c b/dlls/comctl32/tests/header.c
index a3778cf..c62dca2 100644
--- a/dlls/comctl32/tests/header.c
+++ b/dlls/comctl32/tests/header.c
@@ -1524,6 +1524,8 @@ START_TEST(header)
 {
     HWND parent_hwnd;
 
+    winetest_exclusive();
+
     if (!init())
         return;
 
diff --git a/dlls/comctl32/tests/imagelist.c b/dlls/comctl32/tests/imagelist.c
index 0d1770b..76600ec 100644
--- a/dlls/comctl32/tests/imagelist.c
+++ b/dlls/comctl32/tests/imagelist.c
@@ -976,6 +976,9 @@ static void test_imagelist_storage(void)
 START_TEST(imagelist)
 {
     HMODULE hComCtl32 = GetModuleHandle("comctl32.dll");
+
+    winetest_exclusive();
+
     pImageList_DrawIndirect = (void*)GetProcAddress(hComCtl32, "ImageList_DrawIndirect");
     pImageList_SetImageCount = (void*)GetProcAddress(hComCtl32, "ImageList_SetImageCount");
 
diff --git a/dlls/comctl32/tests/listview.c b/dlls/comctl32/tests/listview.c
index 4f8b32d..8069835 100644
--- a/dlls/comctl32/tests/listview.c
+++ b/dlls/comctl32/tests/listview.c
@@ -1216,6 +1216,8 @@ START_TEST(listview)
     HMODULE hComctl32;
     BOOL (WINAPI *pInitCommonControlsEx)(const INITCOMMONCONTROLSEX*);
 
+    winetest_exclusive();
+
     hComctl32 = GetModuleHandleA("comctl32.dll");
     pInitCommonControlsEx = (void*)GetProcAddress(hComctl32, "InitCommonControlsEx");
     if (pInitCommonControlsEx)
diff --git a/dlls/comctl32/tests/monthcal.c b/dlls/comctl32/tests/monthcal.c
index cd9592d..bd167f2 100644
--- a/dlls/comctl32/tests/monthcal.c
+++ b/dlls/comctl32/tests/monthcal.c
@@ -1114,6 +1114,8 @@ START_TEST(monthcal)
     INITCOMMONCONTROLSEX iccex;
     HWND hwnd, parent_wnd;
 
+    winetest_exclusive();
+
     hComctl32 = GetModuleHandleA("comctl32.dll");
     pInitCommonControlsEx = (void*)GetProcAddress(hComctl32, "InitCommonControlsEx");
     if (!pInitCommonControlsEx)
diff --git a/dlls/comctl32/tests/msg.c b/dlls/comctl32/tests/msg.c
index 2129f22..b1fe203 100644
--- a/dlls/comctl32/tests/msg.c
+++ b/dlls/comctl32/tests/msg.c
@@ -248,4 +248,5 @@ void init_msg_sequences(struct msg_sequence **seq, int n)
 
 START_TEST(msg)
 {
+    winetest_exclusive();
 }
diff --git a/dlls/comctl32/tests/progress.c b/dlls/comctl32/tests/progress.c
index 10bbbef..bf9a455 100644
--- a/dlls/comctl32/tests/progress.c
+++ b/dlls/comctl32/tests/progress.c
@@ -222,6 +222,8 @@ static void test_redraw(void)
 
 START_TEST(progress)
 {
+    winetest_exclusive();
+
     init();
     
     test_redraw();
diff --git a/dlls/comctl32/tests/propsheet.c b/dlls/comctl32/tests/propsheet.c
index 45c8d97..1f7b612 100644
--- a/dlls/comctl32/tests/propsheet.c
+++ b/dlls/comctl32/tests/propsheet.c
@@ -201,6 +201,8 @@ static void test_disableowner(void)
 
 START_TEST(propsheet)
 {
+    winetest_exclusive();
+
     test_title();
     test_nopage();
     test_disableowner();
diff --git a/dlls/comctl32/tests/rebar.c b/dlls/comctl32/tests/rebar.c
index e5bea38..fdb18d3 100644
--- a/dlls/comctl32/tests/rebar.c
+++ b/dlls/comctl32/tests/rebar.c
@@ -835,6 +835,8 @@ START_TEST(rebar)
     MSG msg;
     RECT rc;
 
+    winetest_exclusive();
+
     /* LoadLibrary is needed. This file has no references to functions in comctl32 */
     hComctl32 = LoadLibraryA("comctl32.dll");
     pInitCommonControlsEx = (void*)GetProcAddress(hComctl32, "InitCommonControlsEx");
diff --git a/dlls/comctl32/tests/status.c b/dlls/comctl32/tests/status.c
index 4e643c1..e910c92 100644
--- a/dlls/comctl32/tests/status.c
+++ b/dlls/comctl32/tests/status.c
@@ -190,6 +190,8 @@ START_TEST(status)
 {
     hinst = GetModuleHandleA(NULL);
 
+    winetest_exclusive();
+
     InitCommonControls();
 
     test_status_control();
diff --git a/dlls/comctl32/tests/tab.c b/dlls/comctl32/tests/tab.c
index 9489376..cffcc4d 100644
--- a/dlls/comctl32/tests/tab.c
+++ b/dlls/comctl32/tests/tab.c
@@ -961,6 +961,8 @@ START_TEST(tab)
     HWND parent_wnd;
     LOGFONTA logfont;
 
+    winetest_exclusive();
+
     lstrcpyA(logfont.lfFaceName, "Arial");
     memset(&logfont, 0, sizeof(logfont));
     logfont.lfHeight = -12;
diff --git a/dlls/comctl32/tests/toolbar.c b/dlls/comctl32/tests/toolbar.c
index 2693025..1e0d63f 100644
--- a/dlls/comctl32/tests/toolbar.c
+++ b/dlls/comctl32/tests/toolbar.c
@@ -1128,6 +1128,8 @@ START_TEST(toolbar)
     MSG msg;
     RECT rc;
   
+    winetest_exclusive();
+
     InitCommonControls();
   
     wc.style = CS_HREDRAW | CS_VREDRAW;
diff --git a/dlls/comctl32/tests/tooltips.c b/dlls/comctl32/tests/tooltips.c
index e9bce63..53f171f 100644
--- a/dlls/comctl32/tests/tooltips.c
+++ b/dlls/comctl32/tests/tooltips.c
@@ -234,6 +234,8 @@ static void test_customdraw(void) {
 
 START_TEST(tooltips)
 {
+    winetest_exclusive();
+
     InitCommonControls();
 
     test_create_tooltip();
diff --git a/dlls/comctl32/tests/treeview.c b/dlls/comctl32/tests/treeview.c
index c1ba7f3..bc2ecbc 100644
--- a/dlls/comctl32/tests/treeview.c
+++ b/dlls/comctl32/tests/treeview.c
@@ -654,6 +654,8 @@ START_TEST(treeview)
     WNDCLASSA wc;
     MSG msg;
   
+    winetest_exclusive();
+
     hComctl32 = GetModuleHandleA("comctl32.dll");
     pInitCommonControlsEx = (void*)GetProcAddress(hComctl32, "InitCommonControlsEx");
     if (pInitCommonControlsEx)
diff --git a/dlls/comctl32/tests/updown.c b/dlls/comctl32/tests/updown.c
index 6f8e395..5867250 100644
--- a/dlls/comctl32/tests/updown.c
+++ b/dlls/comctl32/tests/updown.c
@@ -585,6 +585,8 @@ static void test_create_updown_control(void)
 
 START_TEST(updown)
 {
+    winetest_exclusive();
+
     InitCommonControls();
     init_msg_sequences(sequences, NUM_MSG_SEQUENCES);
 
diff --git a/dlls/crypt32/tests/msg.c b/dlls/crypt32/tests/msg.c
index e88d382..8b9c562 100644
--- a/dlls/crypt32/tests/msg.c
+++ b/dlls/crypt32/tests/msg.c
@@ -2646,7 +2646,9 @@ static void test_verify_message_signature(void)
 
 START_TEST(msg)
 {
-     init_function_pointers();
+    winetest_exclusive();
+
+    init_function_pointers();
 
     /* Basic parameter checking tests */
     test_msg_open_to_encode();
diff --git a/dlls/d3d8/tests/device.c b/dlls/d3d8/tests/device.c
index d40f196..3273292 100644
--- a/dlls/d3d8/tests/device.c
+++ b/dlls/d3d8/tests/device.c
@@ -1329,6 +1329,8 @@ START_TEST(device)
         return;
     }
 
+    winetest_exclusive();
+
     pDirect3DCreate8 = (void *)GetProcAddress( d3d8_handle, "Direct3DCreate8" );
     ok(pDirect3DCreate8 != NULL, "Failed to get address of Direct3DCreate8\n");
     if (pDirect3DCreate8)
diff --git a/dlls/d3d8/tests/surface.c b/dlls/d3d8/tests/surface.c
index 86fb884..71007be 100644
--- a/dlls/d3d8/tests/surface.c
+++ b/dlls/d3d8/tests/surface.c
@@ -322,6 +322,8 @@ START_TEST(surface)
     HMODULE d3d8_handle;
     IDirect3DDevice8 *device_ptr;
 
+    winetest_exclusive();
+
     d3d8_handle = LoadLibraryA("d3d8.dll");
     if (!d3d8_handle)
     {
diff --git a/dlls/d3d8/tests/texture.c b/dlls/d3d8/tests/texture.c
index a002763..7ab1ef7 100644
--- a/dlls/d3d8/tests/texture.c
+++ b/dlls/d3d8/tests/texture.c
@@ -133,6 +133,8 @@ START_TEST(texture)
     HMODULE d3d8_handle;
     IDirect3DDevice8 *device_ptr;
 
+    winetest_exclusive();
+
     d3d8_handle = LoadLibraryA("d3d8.dll");
     if (!d3d8_handle)
     {
diff --git a/dlls/d3d8/tests/visual.c b/dlls/d3d8/tests/visual.c
index 33d6176..6c48b33 100644
--- a/dlls/d3d8/tests/visual.c
+++ b/dlls/d3d8/tests/visual.c
@@ -1272,6 +1272,8 @@ START_TEST(visual)
     DWORD color;
     D3DCAPS8 caps;
 
+    winetest_exclusive();
+
     d3d8_handle = LoadLibraryA("d3d8.dll");
     if (!d3d8_handle)
     {
diff --git a/dlls/d3d8/tests/volume.c b/dlls/d3d8/tests/volume.c
index aee0c3a..cd0dd57 100644
--- a/dlls/d3d8/tests/volume.c
+++ b/dlls/d3d8/tests/volume.c
@@ -127,6 +127,8 @@ START_TEST(volume)
     IDirect3DDevice8 *device_ptr;
     D3DCAPS8 caps;
 
+    winetest_exclusive();
+
     d3d8_handle = LoadLibraryA("d3d8.dll");
     if (!d3d8_handle)
     {
diff --git a/dlls/d3d9/tests/d3d9ex.c b/dlls/d3d9/tests/d3d9ex.c
index 3917a57..aebbf63 100644
--- a/dlls/d3d9/tests/d3d9ex.c
+++ b/dlls/d3d9/tests/d3d9ex.c
@@ -182,6 +182,8 @@ out:
 
 START_TEST(d3d9ex)
 {
+    winetest_exclusive();
+
     d3d9_handle = LoadLibraryA("d3d9.dll");
     if (!d3d9_handle)
     {
diff --git a/dlls/d3d9/tests/device.c b/dlls/d3d9/tests/device.c
index 3a56298..ff78cd4 100644
--- a/dlls/d3d9/tests/device.c
+++ b/dlls/d3d9/tests/device.c
@@ -2060,6 +2060,8 @@ START_TEST(device)
         return;
     }
 
+    winetest_exclusive();
+
     pDirect3DCreate9 = (void *)GetProcAddress( d3d9_handle, "Direct3DCreate9" );
     ok(pDirect3DCreate9 != NULL, "Failed to get address of Direct3DCreate9\n");
     if (pDirect3DCreate9)
diff --git a/dlls/d3d9/tests/query.c b/dlls/d3d9/tests/query.c
index 6e8b4c9..3ba7e31 100644
--- a/dlls/d3d9/tests/query.c
+++ b/dlls/d3d9/tests/query.c
@@ -240,6 +240,8 @@ START_TEST(query)
         return;
     }
 
+    winetest_exclusive();
+
     pDirect3DCreate9 = (void *)GetProcAddress( d3d9_handle, "Direct3DCreate9" );
     ok(pDirect3DCreate9 != NULL, "Failed to get address of Direct3DCreate9\n");
     if (pDirect3DCreate9)
diff --git a/dlls/d3d9/tests/shader.c b/dlls/d3d9/tests/shader.c
index 07318e3..d333bc6 100644
--- a/dlls/d3d9/tests/shader.c
+++ b/dlls/d3d9/tests/shader.c
@@ -205,6 +205,8 @@ START_TEST(shader)
     D3DCAPS9 caps;
     IDirect3DDevice9 *device_ptr;
 
+    winetest_exclusive();
+
     d3d9_handle = LoadLibraryA("d3d9.dll");
     if (!d3d9_handle)
     {
diff --git a/dlls/d3d9/tests/stateblock.c b/dlls/d3d9/tests/stateblock.c
index ee5061f..2b98b53 100644
--- a/dlls/d3d9/tests/stateblock.c
+++ b/dlls/d3d9/tests/stateblock.c
@@ -1461,6 +1461,8 @@ START_TEST(stateblock)
     D3DPRESENT_PARAMETERS device_pparams;
     HRESULT hret;
 
+    winetest_exclusive();
+
     d3d9_handle = LoadLibraryA("d3d9.dll");
     if (!d3d9_handle)
     {
diff --git a/dlls/d3d9/tests/surface.c b/dlls/d3d9/tests/surface.c
index 69016f5..3a889e0 100644
--- a/dlls/d3d9/tests/surface.c
+++ b/dlls/d3d9/tests/surface.c
@@ -380,6 +380,8 @@ START_TEST(surface)
     HMODULE d3d9_handle;
     IDirect3DDevice9 *device_ptr;
 
+    winetest_exclusive();
+
     d3d9_handle = LoadLibraryA("d3d9.dll");
     if (!d3d9_handle)
     {
diff --git a/dlls/d3d9/tests/texture.c b/dlls/d3d9/tests/texture.c
index bbc98a7..8b64eaf 100644
--- a/dlls/d3d9/tests/texture.c
+++ b/dlls/d3d9/tests/texture.c
@@ -242,6 +242,8 @@ START_TEST(texture)
     HMODULE d3d9_handle;
     IDirect3DDevice9 *device_ptr;
 
+    winetest_exclusive();
+
     d3d9_handle = LoadLibraryA("d3d9.dll");
     if (!d3d9_handle)
     {
diff --git a/dlls/d3d9/tests/vertexdeclaration.c b/dlls/d3d9/tests/vertexdeclaration.c
index 292087f..d16cf1d 100644
--- a/dlls/d3d9/tests/vertexdeclaration.c
+++ b/dlls/d3d9/tests/vertexdeclaration.c
@@ -795,6 +795,8 @@ START_TEST(vertexdeclaration)
     IDirect3DDevice9 *device_ptr = 0;
     IDirect3DVertexDeclaration9 *decl_ptr = 0;
 
+    winetest_exclusive();
+
     d3d9_handle = LoadLibraryA("d3d9.dll");
     if (!d3d9_handle)
     {
diff --git a/dlls/d3d9/tests/visual.c b/dlls/d3d9/tests/visual.c
index 1522523..8405bcf 100644
--- a/dlls/d3d9/tests/visual.c
+++ b/dlls/d3d9/tests/visual.c
@@ -9218,6 +9218,8 @@ START_TEST(visual)
     HRESULT hr;
     DWORD color;
 
+    winetest_exclusive();
+
     d3d9_handle = LoadLibraryA("d3d9.dll");
     if (!d3d9_handle)
     {
diff --git a/dlls/d3d9/tests/volume.c b/dlls/d3d9/tests/volume.c
index 31066a6..120295c 100644
--- a/dlls/d3d9/tests/volume.c
+++ b/dlls/d3d9/tests/volume.c
@@ -124,6 +124,8 @@ START_TEST(volume)
     IDirect3DDevice9 *device_ptr;
     D3DCAPS9 caps;
 
+    winetest_exclusive();
+
     memset(&caps, 0, sizeof(caps));
     d3d9_handle = LoadLibraryA("d3d9.dll");
     if (!d3d9_handle)
diff --git a/dlls/ddraw/tests/ddrawmodes.c b/dlls/ddraw/tests/ddrawmodes.c
index 95e8657..a4991ec 100644
--- a/dlls/ddraw/tests/ddrawmodes.c
+++ b/dlls/ddraw/tests/ddrawmodes.c
@@ -382,6 +382,8 @@ static void testcooperativelevels_exclusive(void)
 
 START_TEST(ddrawmodes)
 {
+    winetest_exclusive();
+
     createwindow();
     if (!createdirectdraw())
         return;
diff --git a/dlls/ddraw/tests/dsurface.c b/dlls/ddraw/tests/dsurface.c
index 7dba28b..ca9b112 100644
--- a/dlls/ddraw/tests/dsurface.c
+++ b/dlls/ddraw/tests/dsurface.c
@@ -2611,6 +2611,8 @@ static void StructSizeTest(void)
 
 START_TEST(dsurface)
 {
+    winetest_exclusive();
+
     if (!CreateDirectDraw())
         return;
     MipMapCreationTest();
diff --git a/dlls/ddraw/tests/visual.c b/dlls/ddraw/tests/visual.c
index ede24eb..8538a0e 100644
--- a/dlls/ddraw/tests/visual.c
+++ b/dlls/ddraw/tests/visual.c
@@ -2607,6 +2607,9 @@ START_TEST(visual)
 {
     HRESULT hr;
     DWORD color;
+
+    winetest_exclusive();
+
     if(!createObjects())
     {
         skip("Cannot initialize DirectDraw and Direct3D, skipping\n");
diff --git a/dlls/dinput/tests/device.c b/dlls/dinput/tests/device.c
index e59d8c3..7452b8e 100644
--- a/dlls/dinput/tests/device.c
+++ b/dlls/dinput/tests/device.c
@@ -186,6 +186,8 @@ static void device_tests(void)
 
 START_TEST(device)
 {
+    winetest_exclusive();
+
     CoInitialize(NULL);
 
     device_tests();
diff --git a/dlls/dinput/tests/keyboard.c b/dlls/dinput/tests/keyboard.c
index d427e65..ace5576 100644
--- a/dlls/dinput/tests/keyboard.c
+++ b/dlls/dinput/tests/keyboard.c
@@ -193,6 +193,8 @@ static void keyboard_tests(DWORD version)
 
 START_TEST(keyboard)
 {
+    winetest_exclusive();
+
     CoInitialize(NULL);
 
     trace("DLL Version: %s\n", get_file_version("dinput.dll"));
diff --git a/dlls/dinput/tests/mouse.c b/dlls/dinput/tests/mouse.c
index 42e5982..978f5ce 100644
--- a/dlls/dinput/tests/mouse.c
+++ b/dlls/dinput/tests/mouse.c
@@ -143,6 +143,8 @@ static void mouse_tests(void)
 
 START_TEST(mouse)
 {
+    winetest_exclusive();
+
     CoInitialize(NULL);
 
     trace("DLL Version: %s\n", get_file_version("dinput.dll"));
diff --git a/dlls/gdi32/tests/clipping.c b/dlls/gdi32/tests/clipping.c
index 0ae3eb6..16290a1 100644
--- a/dlls/gdi32/tests/clipping.c
+++ b/dlls/gdi32/tests/clipping.c
@@ -258,6 +258,8 @@ if (0) /* crashes under Win9x */
 
 START_TEST(clipping)
 {
+    winetest_exclusive();
+
     test_GetRandomRgn();
     test_ExtCreateRegion();
 }
diff --git a/dlls/gdi32/tests/dc.c b/dlls/gdi32/tests/dc.c
index 9e0048e..4b2fe1c 100644
--- a/dlls/gdi32/tests/dc.c
+++ b/dlls/gdi32/tests/dc.c
@@ -255,6 +255,8 @@ static void test_CreateCompatibleDC(void)
 
 START_TEST(dc)
 {
+    winetest_exclusive();
+
     test_savedc();
     test_savedc_2();
     test_GdiConvertToDevmodeW();
diff --git a/dlls/gdi32/tests/font.c b/dlls/gdi32/tests/font.c
index d143949..d71ff34 100644
--- a/dlls/gdi32/tests/font.c
+++ b/dlls/gdi32/tests/font.c
@@ -2397,6 +2397,8 @@ static void test_GetTextFace(void)
 
 START_TEST(font)
 {
+    winetest_exclusive();
+
     init();
 
     test_logfont();
diff --git a/dlls/gdi32/tests/metafile.c b/dlls/gdi32/tests/metafile.c
index 5f295bb..801ca89 100644
--- a/dlls/gdi32/tests/metafile.c
+++ b/dlls/gdi32/tests/metafile.c
@@ -2152,6 +2152,8 @@ static void test_SetEnhMetaFileBits(void)
 
 START_TEST(metafile)
 {
+    winetest_exclusive();
+
     init_function_pointers();
 
     /* For enhanced metafiles (enhmfdrv) */
diff --git a/dlls/gdiplus/tests/font.c b/dlls/gdiplus/tests/font.c
index 0487655..80022e7 100644
--- a/dlls/gdiplus/tests/font.c
+++ b/dlls/gdiplus/tests/font.c
@@ -289,6 +289,8 @@ START_TEST(font)
     struct GdiplusStartupInput gdiplusStartupInput;
     ULONG_PTR gdiplusToken;
 
+    winetest_exclusive();
+
     gdiplusStartupInput.GdiplusVersion              = 1;
     gdiplusStartupInput.DebugEventCallback          = NULL;
     gdiplusStartupInput.SuppressBackgroundThread    = 0;
diff --git a/dlls/gdiplus/tests/image.c b/dlls/gdiplus/tests/image.c
index 38a58b9..0540d24 100644
--- a/dlls/gdiplus/tests/image.c
+++ b/dlls/gdiplus/tests/image.c
@@ -512,6 +512,8 @@ START_TEST(image)
     struct GdiplusStartupInput gdiplusStartupInput;
     ULONG_PTR gdiplusToken;
 
+    winetest_exclusive();
+
     gdiplusStartupInput.GdiplusVersion              = 1;
     gdiplusStartupInput.DebugEventCallback          = NULL;
     gdiplusStartupInput.SuppressBackgroundThread    = 0;
diff --git a/dlls/imm32/tests/imm32.c b/dlls/imm32/tests/imm32.c
index 591feb3..a1e5e47 100644
--- a/dlls/imm32/tests/imm32.c
+++ b/dlls/imm32/tests/imm32.c
@@ -221,6 +221,8 @@ static int test_ImmNotifyIME(void) {
 }
 
 START_TEST(imm32) {
+    winetest_exclusive();
+
     if (init())
         test_ImmNotifyIME();
     cleanup();
diff --git a/dlls/kernel32/tests/thread.c b/dlls/kernel32/tests/thread.c
index d1ac617..386f894 100644
--- a/dlls/kernel32/tests/thread.c
+++ b/dlls/kernel32/tests/thread.c
@@ -1224,6 +1224,8 @@ START_TEST(thread)
        return;
    }
 
+   winetest_exclusive();
+
    test_CreateRemoteThread();
    test_CreateThread_basic();
    test_CreateThread_suspended();
diff --git a/dlls/mshtml/tests/htmldoc.c b/dlls/mshtml/tests/htmldoc.c
index 5e95448..08d9139 100644
--- a/dlls/mshtml/tests/htmldoc.c
+++ b/dlls/mshtml/tests/htmldoc.c
@@ -4092,6 +4092,8 @@ static void gecko_installer_workaround(BOOL disable)
 
 START_TEST(htmldoc)
 {
+    winetest_exclusive();
+
     gecko_installer_workaround(TRUE);
 
     CoInitialize(NULL);
diff --git a/dlls/ole32/tests/compobj.c b/dlls/ole32/tests/compobj.c
index b2aaa22..677ec64 100644
--- a/dlls/ole32/tests/compobj.c
+++ b/dlls/ole32/tests/compobj.c
@@ -1021,6 +1021,9 @@ static void test_CoGetObjectContext(void)
 START_TEST(compobj)
 {
     HMODULE hOle32 = GetModuleHandle("ole32");
+
+    winetest_exclusive();
+
     pCoGetObjectContext = (void*)GetProcAddress(hOle32, "CoGetObjectContext");
     if (!(pCoInitializeEx = (void*)GetProcAddress(hOle32, "CoInitializeEx")))
     {
diff --git a/dlls/ole32/tests/marshal.c b/dlls/ole32/tests/marshal.c
index fba8b14..74bfd2a 100644
--- a/dlls/ole32/tests/marshal.c
+++ b/dlls/ole32/tests/marshal.c
@@ -2995,6 +2995,8 @@ START_TEST(marshal)
         return;
     }
 
+    winetest_exclusive();
+
     register_test_window();
 
     test_cocreateinstance_proxy();
diff --git a/dlls/opengl32/tests/opengl.c b/dlls/opengl32/tests/opengl.c
index e72d1a0..9d1dfc1 100644
--- a/dlls/opengl32/tests/opengl.c
+++ b/dlls/opengl32/tests/opengl.c
@@ -432,6 +432,8 @@ START_TEST(opengl)
         0, 0, 0                /* layer masks */
     };
 
+    winetest_exclusive();
+
     hwnd = CreateWindow("static", "Title", WS_OVERLAPPEDWINDOW,
                         10, 10, 200, 200, NULL, NULL, NULL, NULL);
     ok(hwnd != NULL, "err: %d\n", GetLastError());
diff --git a/dlls/qmgr/tests/enum_files.c b/dlls/qmgr/tests/enum_files.c
index eeb8009..aca563a 100644
--- a/dlls/qmgr/tests/enum_files.c
+++ b/dlls/qmgr/tests/enum_files.c
@@ -279,6 +279,8 @@ START_TEST(enum_files)
     };
     const test_t *test;
 
+    winetest_exclusive();
+
     CoInitialize(NULL);
     for (test = tests; *test; ++test)
     {
diff --git a/dlls/qmgr/tests/enum_jobs.c b/dlls/qmgr/tests/enum_jobs.c
index f95404c..9bde1d1 100644
--- a/dlls/qmgr/tests/enum_jobs.c
+++ b/dlls/qmgr/tests/enum_jobs.c
@@ -307,6 +307,8 @@ START_TEST(enum_jobs)
     };
     const test_t *test;
 
+    winetest_exclusive();
+
     CoInitialize(NULL);
     for (test = tests; *test; ++test)
     {
diff --git a/dlls/qmgr/tests/file.c b/dlls/qmgr/tests/file.c
index 033b2c5..70ab3c6 100644
--- a/dlls/qmgr/tests/file.c
+++ b/dlls/qmgr/tests/file.c
@@ -177,6 +177,8 @@ START_TEST(file)
     };
     const test_t *test;
 
+    winetest_exclusive();
+
     CoInitialize(NULL);
     for (test = tests; *test; ++test)
     {
diff --git a/dlls/qmgr/tests/job.c b/dlls/qmgr/tests/job.c
index 36201f8..cb58391 100644
--- a/dlls/qmgr/tests/job.c
+++ b/dlls/qmgr/tests/job.c
@@ -498,6 +498,8 @@ START_TEST(job)
     };
     const test_t *test;
 
+    winetest_exclusive();
+
     if (!init_paths())
         return;
 
diff --git a/dlls/qmgr/tests/qmgr.c b/dlls/qmgr/tests/qmgr.c
index 8c95586..d30f753 100644
--- a/dlls/qmgr/tests/qmgr.c
+++ b/dlls/qmgr/tests/qmgr.c
@@ -231,6 +232,8 @@ START_TEST(qmgr)
         do_child(argv[2]);
     else
     {
+        winetest_exclusive();
+
         test_CreateInstance();
         test_CreateJob();
         test_EnumJobs();
diff --git a/dlls/riched20/tests/richole.c b/dlls/riched20/tests/richole.c
index 6eefdd0..5107ef8 100644
--- a/dlls/riched20/tests/richole.c
+++ b/dlls/riched20/tests/richole.c
@@ -60,6 +60,8 @@ START_TEST(richole)
   HRESULT hres;
   LRESULT res;
   HWND w;
+ 
+  winetest_exclusive();
 
   /* Must explicitly LoadLibrary(). The test has no references to functions in
    * RICHED20.DLL, so the linker doesn't actually link to it. */
diff --git a/dlls/shdocvw/tests/webbrowser.c b/dlls/shdocvw/tests/webbrowser.c
index 86d38db..6ba9586 100644
--- a/dlls/shdocvw/tests/webbrowser.c
+++ b/dlls/shdocvw/tests/webbrowser.c
@@ -2069,6 +2069,8 @@ static void gecko_installer_workaround(BOOL disable)
 
 START_TEST(webbrowser)
 {
+    winetest_exclusive();
+
     gecko_installer_workaround(TRUE);
 
     container_hwnd = create_container_window();
diff --git a/dlls/shell32/tests/systray.c b/dlls/shell32/tests/systray.c
index c672d67..56ea316 100644
--- a/dlls/shell32/tests/systray.c
+++ b/dlls/shell32/tests/systray.c
@@ -138,6 +138,8 @@ START_TEST(systray)
     RECT rc;
     HMODULE huser32, hshell32;
 
+    winetest_exclusive();
+
     hshell32 = GetModuleHandleA("shell32.dll");
     pShell_NotifyIconW = (void*)GetProcAddress(hshell32, "Shell_NotifyIconW");
 
diff --git a/dlls/shlwapi/tests/shreg.c b/dlls/shlwapi/tests/shreg.c
index 77a47e2..f529d21 100644
--- a/dlls/shlwapi/tests/shreg.c
+++ b/dlls/shlwapi/tests/shreg.c
@@ -378,8 +378,11 @@ static void test_SHDeleteKey(void)
 
 START_TEST(shreg)
 {
-	HKEY hkey = create_test_entries();
+	HKEY hkey;
 
+        winetest_exclusive();
+
+	hkey = create_test_entries();
         if (!hkey) return;
 
 	hshlwapi = GetModuleHandleA("shlwapi.dll");
diff --git a/dlls/user32/tests/broadcast.c b/dlls/user32/tests/broadcast.c
index c88cee7..7531921 100644
--- a/dlls/user32/tests/broadcast.c
+++ b/dlls/user32/tests/broadcast.c
@@ -333,6 +333,8 @@ static void test_noprivileges(void)
 
 START_TEST(broadcast)
 {
+    winetest_exclusive();
+
     if (!init_procs())
         return;
 
diff --git a/dlls/user32/tests/class.c b/dlls/user32/tests/class.c
index 8412e8b..caf5864 100644
--- a/dlls/user32/tests/class.c
+++ b/dlls/user32/tests/class.c
@@ -829,6 +829,8 @@ static void WINAPI CreateDialogParamTest(HINSTANCE hInstance)
 
 START_TEST(class)
 {
+    winetest_exclusive();
+
     HANDLE hInstance = GetModuleHandleA( NULL );
 
     if (!GetModuleHandleW(0))
diff --git a/dlls/user32/tests/clipboard.c b/dlls/user32/tests/clipboard.c
index 30b1707..84ee658 100644
--- a/dlls/user32/tests/clipboard.c
+++ b/dlls/user32/tests/clipboard.c
@@ -192,6 +192,8 @@ todo_wine
 
 START_TEST(clipboard)
 {
+    winetest_exclusive();
+
     SetLastError(0xdeadbeef);
     FindAtomW(NULL);
     if (GetLastError() == ERROR_CALL_NOT_IMPLEMENTED) is_win9x = TRUE;
diff --git a/dlls/user32/tests/combo.c b/dlls/user32/tests/combo.c
index d47ff20..dd65dec 100644
--- a/dlls/user32/tests/combo.c
+++ b/dlls/user32/tests/combo.c
@@ -354,6 +354,8 @@ static void test_WM_LBUTTONDOWN(void)
 
 START_TEST(combo)
 {
+    winetest_exclusive();
+
     hMainWnd = CreateWindow("static", "Test", WS_OVERLAPPEDWINDOW, 10, 10, 300, 300, NULL, NULL, NULL, 0);
     ShowWindow(hMainWnd, SW_SHOW);
 
diff --git a/dlls/user32/tests/cursoricon.c b/dlls/user32/tests/cursoricon.c
index e00c45e..e233a9b 100644
--- a/dlls/user32/tests/cursoricon.c
+++ b/dlls/user32/tests/cursoricon.c
@@ -948,6 +948,8 @@ START_TEST(cursoricon)
         return;
     }
 
+    winetest_exclusive();
+
     test_CopyImage_Bitmap(1);
     test_CopyImage_Bitmap(4);
     test_CopyImage_Bitmap(8);
diff --git a/dlls/user32/tests/dce.c b/dlls/user32/tests/dce.c
index fead385..c0560dd 100644
--- a/dlls/user32/tests/dce.c
+++ b/dlls/user32/tests/dce.c
@@ -396,6 +396,8 @@ START_TEST(dce)
 {
     WNDCLASSA cls;
 
+    winetest_exclusive();
+
     cls.style = CS_DBLCLKS;
     cls.lpfnWndProc = DefWindowProcA;
     cls.cbClsExtra = 0;
diff --git a/dlls/user32/tests/dde.c b/dlls/user32/tests/dde.c
index 56c8893..88e93fd 100644
--- a/dlls/user32/tests/dde.c
+++ b/dlls/user32/tests/dde.c
@@ -2102,6 +2102,8 @@ START_TEST(dde)
         return;
     }
 
+    winetest_exclusive();
+
     ZeroMemory(&startup, sizeof(STARTUPINFO));
     sprintf(buffer, "%s dde ddeml", argv[0]);
     startup.cb = sizeof(startup);
diff --git a/dlls/user32/tests/dialog.c b/dlls/user32/tests/dialog.c
index 8bf3c29..ae9b7e4 100644
--- a/dlls/user32/tests/dialog.c
+++ b/dlls/user32/tests/dialog.c
@@ -923,6 +923,8 @@ static void test_DisabledDialogTest(void)
 
 START_TEST(dialog)
 {
+    winetest_exclusive();
+
     g_hinst = GetModuleHandleA (0);
 
     if (!RegisterWindowClasses()) assert(0);
diff --git a/dlls/user32/tests/edit.c b/dlls/user32/tests/edit.c
index 0c5a678..0df1a54 100644
--- a/dlls/user32/tests/edit.c
+++ b/dlls/user32/tests/edit.c
@@ -1991,6 +1991,8 @@ static void UnregisterWindowClasses (void)
 
 START_TEST(edit)
 {
+    winetest_exclusive();
+
     hinst = GetModuleHandleA(NULL);
     assert(RegisterWindowClasses());
 
diff --git a/dlls/user32/tests/input.c b/dlls/user32/tests/input.c
index 37198d3..bc5f70d 100644
--- a/dlls/user32/tests/input.c
+++ b/dlls/user32/tests/input.c
@@ -1167,6 +1167,8 @@ static void test_key_map(void)
 
 START_TEST(input)
 {
+    winetest_exclusive();
+
     init_function_pointers();
 
     if (!pSendInput)
diff --git a/dlls/user32/tests/listbox.c b/dlls/user32/tests/listbox.c
index 849372c..263c76a 100644
--- a/dlls/user32/tests/listbox.c
+++ b/dlls/user32/tests/listbox.c
@@ -1509,6 +1509,8 @@ START_TEST(listbox)
      {     2,      2,      2, LB_ERR}, {0,0,0,0},
      {LB_ERR, LB_ERR,      0, LB_ERR}, {0,0,0,0}};
 
+  winetest_exclusive();
+
   trace (" Testing single selection...\n");
   check (SS);
   trace (" ... with NOSEL\n");
diff --git a/dlls/user32/tests/menu.c b/dlls/user32/tests/menu.c
index 1aa2eb6..4392115 100644
--- a/dlls/user32/tests/menu.c
+++ b/dlls/user32/tests/menu.c
@@ -2340,6 +2340,8 @@ static void test_InsertMenu(void)
 
 START_TEST(menu)
 {
+    winetest_exclusive();
+
     init_function_pointers();
 
     register_menu_check_class();
diff --git a/dlls/user32/tests/msg.c b/dlls/user32/tests/msg.c
index dfb6108..12f4418 100644
--- a/dlls/user32/tests/msg.c
+++ b/dlls/user32/tests/msg.c
@@ -10918,6 +10918,8 @@ START_TEST(msg)
     BOOL ret;
     FARPROC pIsWinEventHookInstalled = 0;/*GetProcAddress(user32, "IsWinEventHookInstalled");*/
 
+    winetest_exclusive();
+
     init_procs();
 
     if (!RegisterWindowClasses()) assert(0);
diff --git a/dlls/user32/tests/scroll.c b/dlls/user32/tests/scroll.c
index 3bc407a..4dfd46a 100644
--- a/dlls/user32/tests/scroll.c
+++ b/dlls/user32/tests/scroll.c
@@ -131,6 +131,8 @@ START_TEST ( scroll )
 {
     WNDCLASSA wc;
 
+    winetest_exclusive();
+
     wc.style = CS_HREDRAW | CS_VREDRAW;
     wc.cbClsExtra = 0;
     wc.cbWndExtra = 0;
diff --git a/dlls/user32/tests/static.c b/dlls/user32/tests/static.c
index 7810db4..9381c96 100644
--- a/dlls/user32/tests/static.c
+++ b/dlls/user32/tests/static.c
@@ -99,6 +99,8 @@ START_TEST(static)
     static char szClassName[] = "testclass";
     WNDCLASSEX  wndclass;
 
+    winetest_exclusive();
+
     wndclass.cbSize         = sizeof(wndclass);
     wndclass.style          = CS_HREDRAW | CS_VREDRAW;
     wndclass.lpfnWndProc    = WndProc;
diff --git a/dlls/user32/tests/sysparams.c b/dlls/user32/tests/sysparams.c
index f899dab..45789cc 100644
--- a/dlls/user32/tests/sysparams.c
+++ b/dlls/user32/tests/sysparams.c
@@ -2660,6 +2660,8 @@ START_TEST(sysparams)
     DWORD dwThreadId;
     HANDLE hInstance, hdll;
 
+    winetest_exclusive();
+
     hdll = GetModuleHandleA("user32.dll");
     pChangeDisplaySettingsExA=(void*)GetProcAddress(hdll, "ChangeDisplaySettingsExA");
 
diff --git a/dlls/user32/tests/text.c b/dlls/user32/tests/text.c
index 1e09650..d8ab589 100644
--- a/dlls/user32/tests/text.c
+++ b/dlls/user32/tests/text.c
@@ -307,6 +307,8 @@ static void test_DrawState(void)
 
 START_TEST(text)
 {
+    winetest_exclusive();
+
     test_TabbedText();
     test_DrawTextCalcRect();
     test_DrawState();
diff --git a/dlls/user32/tests/win.c b/dlls/user32/tests/win.c
index 6cb784f..3cce45d 100644
--- a/dlls/user32/tests/win.c
+++ b/dlls/user32/tests/win.c
@@ -4805,6 +4805,8 @@ static void test_hwnd_message(void)
 
 START_TEST(win)
 {
+    winetest_exclusive();
+
     pGetAncestor = (void *)GetProcAddress( GetModuleHandleA("user32.dll"), "GetAncestor" );
     pGetWindowInfo = (void *)GetProcAddress( GetModuleHandleA("user32.dll"), "GetWindowInfo" );
     pGetWindowModuleFileNameA = (void *)GetProcAddress( GetModuleHandleA("user32.dll"), "GetWindowModuleFileNameA" );
diff --git a/dlls/user32/tests/winstation.c b/dlls/user32/tests/winstation.c
index 42f2644..baeaeb2 100644
--- a/dlls/user32/tests/winstation.c
+++ b/dlls/user32/tests/winstation.c
@@ -350,6 +350,8 @@ static void test_enumdesktops(void)
 
 START_TEST(winstation)
 {
+    winetest_exclusive();
+
     /* Check whether this platform supports WindowStation calls */
 
     SetLastError( 0xdeadbeef );
diff --git a/dlls/usp10/tests/usp10.c b/dlls/usp10/tests/usp10.c
index 0705904..e2e74ff 100644
--- a/dlls/usp10/tests/usp10.c
+++ b/dlls/usp10/tests/usp10.c
@@ -1378,6 +1378,8 @@ START_TEST(usp10)
 
     unsigned short  pwOutGlyphs[256];
 
+    winetest_exclusive();
+
     /* We need a valid HDC to drive a lot of Script functions which requires the following    *
      * to set up for the tests.                                                               */
     hwnd = CreateWindowExA(0, "static", "", WS_POPUP, 0,0,100,100,
diff --git a/dlls/uxtheme/tests/system.c b/dlls/uxtheme/tests/system.c
index ef9c08a..6267980 100644
--- a/dlls/uxtheme/tests/system.c
+++ b/dlls/uxtheme/tests/system.c
@@ -480,6 +480,8 @@ static void test_CloseThemeData(void)
 
 START_TEST(system)
 {
+    winetest_exclusive();
+
     if(!InitFunctionPtrs())
         return;
 
diff --git a/include/wine/test.h b/include/wine/test.h
index 02fc391..7319e8a 100644
--- a/include/wine/test.h
+++ b/include/wine/test.h
@@ -61,6 +61,7 @@ extern int winetest_loop_todo(void);
 extern void winetest_end_todo( const char* platform );
 extern int winetest_get_mainargs( char*** pargv );
 extern void winetest_wait_child_process( HANDLE process );
+extern void winetest_exclusive(void);
 
 #ifdef STANDALONE
 #define START_TEST(name) \
@@ -215,6 +216,41 @@ static tls_data* get_tls_data(void)
     return data;
 }
 
+/* Call this function near the top of the START_TEST() block 
+ * for tests that can't run in parallel with other tests.
+ * This will block other tests that also require those resources from
+ * running until this process exits.
+ * If locking fails for some reason, the function simply returns.
+ */
+void winetest_exclusive(void)
+{
+    HANDLE hLockfile;
+    OVERLAPPED overlap;
+    char filename[1024];
+
+    if (!GetTempPathA(sizeof(filename), filename))
+        return;
+
+    strcat(filename, "\\winetest.lck");
+    hLockfile = CreateFileA( filename, GENERIC_READ | GENERIC_WRITE,
+                          FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
+                          CREATE_ALWAYS, 0, 0 );
+    if (hLockfile == INVALID_HANDLE_VALUE)
+        return;
+
+    memset(&overlap, 0, sizeof(overlap));
+    /* Sigh. Wine doesn't support blocking LockFileEx yet; you have to use an event. */
+    overlap.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
+    /* You have to tell win32 that this event is not for completion */
+    overlap.hEvent = (HANDLE) ((DWORD) (overlap.hEvent) | 1);
+    if (LockFileEx( hLockfile, LOCKFILE_EXCLUSIVE_LOCK, 0, 1, 0, &overlap )) {
+        WaitForSingleObjectEx(overlap.hEvent, INFINITE, FALSE);
+        CloseHandle(overlap.hEvent);
+    }
+
+    /* CloseHandle(hLockfile); Leak the handle for now, else lock is released? */
+}
+
 static void exit_process( int code )
 {
     fflush( stdout );