diff --git a/reactos/drivers/wdm/audio/backpln/portcls/private.h b/reactos/drivers/wdm/audio/backpln/portcls/private.h
index f73dfb26198..7ff45546244 100644
--- a/reactos/drivers/wdm/audio/backpln/portcls/private.h
+++ b/reactos/drivers/wdm/audio/backpln/portcls/private.h
@@ -164,6 +164,7 @@ typedef struct
     PDEVICE_OBJECT PhysicalDeviceObject;
     PDEVICE_OBJECT PrevDeviceObject;
     PCPFNSTARTDEVICE StartDevice;
+    ULONG_PTR Unused[4];
     IAdapterPowerManagement * AdapterPowerManagement;
     ULONG MaxSubDevices;
     KSOBJECT_CREATE_ITEM * CreateItems;