diff --git a/native/text-input-helper/NativeMethods.cs b/native/text-input-helper/NativeMethods.cs
index 4d651c1..1582b75 100644
--- a/native/text-input-helper/NativeMethods.cs
+++ b/native/text-input-helper/NativeMethods.cs
@@ -84,7 +84,7 @@ private struct INPUT
         internal INPUTUNION InputUnion;
     }
 
-    [StructLayout(LayoutKind.Explicit)]
+    [StructLayout(LayoutKind.Explicit, Size = 32)]
     private struct INPUTUNION
     {
         [FieldOffset(0)]