diff --git a/ntpebteb.h b/ntpebteb.h
index 8c8ef31..1b44549 100644
--- a/ntpebteb.h
+++ b/ntpebteb.h
@@ -308,7 +308,9 @@ typedef struct _TEB
 #endif
 
     BOOLEAN InstrumentationCallbackDisabled;
+#ifdef _WIN64
     BOOLEAN UnalignedLoadStoreExceptions;
+#endif
 #ifndef _WIN64
     UCHAR SpareBytes[23];
     ULONG TxFsContext;