diff --git a/app/routes.js b/app/routes.js
index 63d3a9a..9b57bdb 100644
--- a/app/routes.js
+++ b/app/routes.js
@@ -74,9 +74,9 @@ use(async (req, res, next) => {
 
       logger.info('fileDir', fileDir)
 
-      const  mingw_home=process.env.MINGW_HOME;
-      if (mingw_home){
-        if(! fileDir.includes(':')){
+      const  msystem=process.env.MSYSTEM;
+      if (msystem){
+       if(! fileDir.includes(':')){
           // fileDir is unix-like:      /Z/x/y/...., 'Z' means Z:
           // the win-like fileDir should be: Z:\x\y...
           const cygpath = 'cygpath.exe'