diff --git a/setupapi/types_windows.go b/setupapi/types_windows.go
index fa47a5a..e407f77 100644
--- a/setupapi/types_windows.go
+++ b/setupapi/types_windows.go
@@ -249,7 +249,6 @@ const (
 	DIF_NEWDEVICEWIZARD_PREANALYZE     DI_FUNCTION = 0x0000001C
 	DIF_NEWDEVICEWIZARD_POSTANALYZE    DI_FUNCTION = 0x0000001D
 	DIF_NEWDEVICEWIZARD_FINISHINSTALL  DI_FUNCTION = 0x0000001E
-	DIF_UNUSED1                        DI_FUNCTION = 0x0000001F
 	DIF_INSTALLINTERFACES              DI_FUNCTION = 0x00000020
 	DIF_DETECTCANCEL                   DI_FUNCTION = 0x00000021
 	DIF_REGISTER_COINSTALLERS          DI_FUNCTION = 0x00000022