diff --git a/nt/install.bat b/nt/install.bat
index 6a8b4deee4c..d506efe9d2f 100755
--- a/nt/install.bat
+++ b/nt/install.bat
@@ -1,6 +1,7 @@
-nmake -f makefile.nt install
 @echo off
 if (%1) == (speed) set BUILD_TYPE=spd
 if (%1) == (speed) shift
 if not (%1) == () set INSTALL_DIR=%1
-@if not (%1) == () set INSTALL_DIR=%1
+nmake -f makefile.nt install
+set INSTALL_DIR=
+set BUILD_TYPE=