diff --git a/reactos/include/ndk/lpctypes.h b/reactos/include/ndk/lpctypes.h
index 44419618d5d..2f869a8d9e9 100644
--- a/reactos/include/ndk/lpctypes.h
+++ b/reactos/include/ndk/lpctypes.h
@@ -209,8 +209,11 @@ typedef struct _LPCP_PORT_OBJECT
     SECURITY_CLIENT_CONTEXT StaticSecurity;
     LIST_ENTRY LpcReplyChainHead;
     LIST_ENTRY LpcDataInfoChainHead;
-    PEPROCESS ServerProcess;
-    PEPROCESS MappingProcess;
+    union
+    {
+        PEPROCESS ServerProcess;
+        PEPROCESS MappingProcess;
+    };
     ULONG MaxMessageLength;
     ULONG MaxConnectionInfoLength;
     ULONG Flags;