webpack 
 
 windows 
 Delete the entire node-modules folder 
 and then try npm I again 
 your error report has nothing to do with node-sass 
 is a problem with another dependency package 
 did you install node-sass successfully? I feel like you didn't install it successfully. 
 try installing it with cnpm. 
npm install -g cnpm
cnpm install sass-loader node-sass --save-dev
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