diff --git a/vcbuild.bat b/vcbuild.bat
index a86e2369..698044df 100644
--- a/vcbuild.bat
+++ b/vcbuild.bat
@@ -43,6 +43,9 @@ shift
 goto next-arg
 :args-done
 
+if defined WindowsSDKDir goto select-target
+if defined VCINSTALLDIR goto select-target
+
 @rem Look for Visual Studio 2017 only if explicitly requested.
 if "%target_env%" NEQ "vs2017" goto vs-set-2015
 echo Looking for Visual Studio 2017