diff --git a/source/d3d8to9_surface.cpp b/source/d3d8to9_surface.cpp
index b325be7..198ad0f 100644
--- a/source/d3d8to9_surface.cpp
+++ b/source/d3d8to9_surface.cpp
@@ -91,6 +91,18 @@ HRESULT STDMETHODCALLTYPE Direct3DSurface8::GetDesc(D3DSURFACE_DESC8 *pDesc)
 }
 HRESULT STDMETHODCALLTYPE Direct3DSurface8::LockRect(D3DLOCKED_RECT *pLockedRect, const RECT *pRect, DWORD Flags)
 {
+	D3DSURFACE_DESC8 SurfaceDesc;
+
+	const HRESULT hr = GetDesc(&SurfaceDesc);
+
+	// D3D8 clears the contents of pLockedRect for all
+	// surfaces except those of type D3DRTYPE_TEXTURE
+	if (SUCCEEDED(hr) && pLockedRect != nullptr && SurfaceDesc.Type != D3DRTYPE_TEXTURE)
+	{
+		pLockedRect->pBits = nullptr;
+		pLockedRect->Pitch = 0;
+	}
+
 	return ProxyInterface->LockRect(pLockedRect, pRect, Flags);
 }
 HRESULT STDMETHODCALLTYPE Direct3DSurface8::UnlockRect()
diff --git a/source/d3d8to9_volume.cpp b/source/d3d8to9_volume.cpp
index 3bb9428..3e3ffad 100644
--- a/source/d3d8to9_volume.cpp
+++ b/source/d3d8to9_volume.cpp
@@ -90,6 +90,14 @@ HRESULT STDMETHODCALLTYPE Direct3DVolume8::GetDesc(D3DVOLUME_DESC8 *pDesc)
 }
 HRESULT STDMETHODCALLTYPE Direct3DVolume8::LockBox(D3DLOCKED_BOX *pLockedVolume, const D3DBOX *pBox, DWORD Flags)
 {
+	if (pLockedVolume != nullptr)
+	{
+		// D3D8 clears the contents of pLockedVolume
+		pLockedVolume->pBits = nullptr;
+		pLockedVolume->RowPitch = 0;
+		pLockedVolume->SlicePitch = 0;
+	}
+
 	return ProxyInterface->LockBox(pLockedVolume, pBox, Flags);
 }
 HRESULT STDMETHODCALLTYPE Direct3DVolume8::UnlockBox()