diff --git a/basis/windows/ddk/setupapi/setupapi.factor b/basis/windows/ddk/setupapi/setupapi.factor
index ff9ceb4c1e..f10215d5a2 100755
--- a/basis/windows/ddk/setupapi/setupapi.factor
+++ b/basis/windows/ddk/setupapi/setupapi.factor
@@ -404,11 +404,11 @@ CONSTANT: SPID_ACTIVE               $ SPINT_ACTIVE
 CONSTANT: SPID_DEFAULT              $ SPINT_DEFAULT
 CONSTANT: SPID_REMOVED              $ SPINT_REMOVED
 
-STRUCT: SP_DEVICE_INTERFACE_DETAIL_DATA_A
+PACKED-STRUCT: SP_DEVICE_INTERFACE_DETAIL_DATA_A
     { cbSize     DWORD               }
     { DevicePath CHAR[ANYSIZE_ARRAY] } ;
 TYPEDEF: SP_DEVICE_INTERFACE_DETAIL_DATA_A* PSP_DEVICE_INTERFACE_DETAIL_DATA_A
-STRUCT: SP_DEVICE_INTERFACE_DETAIL_DATA_W
+PACKED-STRUCT: SP_DEVICE_INTERFACE_DETAIL_DATA_W
     { cbSize      DWORD                }
     { DevicePath  WCHAR[ANYSIZE_ARRAY] } ;
 TYPEDEF: SP_DEVICE_INTERFACE_DETAIL_DATA_W* PSP_DEVICE_INTERFACE_DETAIL_DATA_W