diff --git a/reactos/drivers/wdm/audio/legacy/wdmaud/interface.h b/reactos/drivers/wdm/audio/legacy/wdmaud/interface.h
index e541453fbc6..af0c9d91d2b 100644
--- a/reactos/drivers/wdm/audio/legacy/wdmaud/interface.h
+++ b/reactos/drivers/wdm/audio/legacy/wdmaud/interface.h
@@ -26,7 +26,7 @@ typedef enum
 typedef struct
 {
     SOUND_DEVICE_TYPE DeviceType;
-    ULONG DeviceIndex;
+    ULONG_PTR DeviceIndex;
 
     HANDLE hDevice;
     ULONG DeviceCount;