diff --git a/dlls/wineoss.drv/mmdevdrv.c b/dlls/wineoss.drv/mmdevdrv.c
index 0db7bb75f1e..bbc26b1e684 100644
--- a/dlls/wineoss.drv/mmdevdrv.c
+++ b/dlls/wineoss.drv/mmdevdrv.c
@@ -101,6 +101,7 @@ struct ACImpl {
     LONG ref;
 
     IMMDevice *parent;
+    IUnknown *pUnkFTMarshal;
 
     WAVEFORMATEX *fmt;
 
@@ -595,6 +596,7 @@ HRESULT WINAPI AUDDRV_GetAudioEndpoint(GUID *guid, IMMDevice *dev,
 {
     ACImpl *This;
     const OSSDevice *oss_dev;
+    HRESULT hr;
 
     TRACE("%s %p %p\n", debugstr_guid(guid), dev, out);
 
@@ -608,6 +610,13 @@ HRESULT WINAPI AUDDRV_GetAudioEndpoint(GUID *guid, IMMDevice *dev,
     if(!This)
         return E_OUTOFMEMORY;
 
+    hr = CoCreateFreeThreadedMarshaler((IUnknown *)&This->IAudioClient_iface,
+        (IUnknown **)&This->pUnkFTMarshal);
+    if (FAILED(hr)) {
+         HeapFree(GetProcessHeap(), 0, This);
+         return hr;
+    }
+
     if(oss_dev->flow == eRender)
         This->fd = open(oss_dev->devnode, O_WRONLY | O_NONBLOCK, 0);
     else if(oss_dev->flow == eCapture)
@@ -672,6 +681,7 @@ HRESULT WINAPI AUDDRV_GetAudioEndpoint(GUID *guid, IMMDevice *dev,
 static HRESULT WINAPI AudioClient_QueryInterface(IAudioClient *iface,
         REFIID riid, void **ppv)
 {
+    ACImpl *This = impl_from_IAudioClient(iface);
     TRACE("(%p)->(%s, %p)\n", iface, debugstr_guid(riid), ppv);
 
     if(!ppv)
@@ -679,6 +689,8 @@ static HRESULT WINAPI AudioClient_QueryInterface(IAudioClient *iface,
     *ppv = NULL;
     if(IsEqualIID(riid, &IID_IUnknown) || IsEqualIID(riid, &IID_IAudioClient))
         *ppv = iface;
+    else if(IsEqualIID(riid, &IID_IMarshal))
+        return IUnknown_QueryInterface(This->pUnkFTMarshal, riid, ppv);
     if(*ppv){
         IUnknown_AddRef((IUnknown*)*ppv);
         return S_OK;
@@ -705,6 +717,7 @@ static ULONG WINAPI AudioClient_Release(IAudioClient *iface)
     if(!ref){
         IAudioClient_Stop(iface);
         IMMDevice_Release(This->parent);
+        IUnknown_Release(This->pUnkFTMarshal);
         This->lock.DebugInfo->Spare[0] = 0;
         DeleteCriticalSection(&This->lock);
         close(This->fd);
@@ -1750,6 +1763,7 @@ static const IAudioClientVtbl AudioClient_Vtbl =
 static HRESULT WINAPI AudioRenderClient_QueryInterface(
         IAudioRenderClient *iface, REFIID riid, void **ppv)
 {
+    ACImpl *This = impl_from_IAudioRenderClient(iface);
     TRACE("(%p)->(%s, %p)\n", iface, debugstr_guid(riid), ppv);
 
     if(!ppv)
@@ -1759,6 +1773,8 @@ static HRESULT WINAPI AudioRenderClient_QueryInterface(
     if(IsEqualIID(riid, &IID_IUnknown) ||
             IsEqualIID(riid, &IID_IAudioRenderClient))
         *ppv = iface;
+    else if(IsEqualIID(riid, &IID_IMarshal))
+        return IUnknown_QueryInterface(This->pUnkFTMarshal, riid, ppv);
     if(*ppv){
         IUnknown_AddRef((IUnknown*)*ppv);
         return S_OK;
@@ -1911,6 +1927,7 @@ static const IAudioRenderClientVtbl AudioRenderClient_Vtbl = {
 static HRESULT WINAPI AudioCaptureClient_QueryInterface(
         IAudioCaptureClient *iface, REFIID riid, void **ppv)
 {
+    ACImpl *This = impl_from_IAudioCaptureClient(iface);
     TRACE("(%p)->(%s, %p)\n", iface, debugstr_guid(riid), ppv);
 
     if(!ppv)
@@ -1920,6 +1937,8 @@ static HRESULT WINAPI AudioCaptureClient_QueryInterface(
     if(IsEqualIID(riid, &IID_IUnknown) ||
             IsEqualIID(riid, &IID_IAudioCaptureClient))
         *ppv = iface;
+    else if(IsEqualIID(riid, &IID_IMarshal))
+        return IUnknown_QueryInterface(This->pUnkFTMarshal, riid, ppv);
     if(*ppv){
         IUnknown_AddRef((IUnknown*)*ppv);
         return S_OK;