title: events.js:160 throw er; // Unhandled 'error' event
body: <p>The project I worked on was built with gulp. </p>
  
  <p>Recently I updated the node version to v6.3.1. Then something came wrong. </p>
  
  <p>A task named 'html' throws an error. Here is the part of error code of it.</p>
  
  <pre><code>bogon:toClient work$ gulp html
  (node:2519) fs: re-evaluating native module sources is not supported. If you are using the graceful-fs module, please update it to a more recent version.
  
  [10:26:10] Using gulpfile ~/Project/TIME_Cancer_Treatment_Centers_of_America(CTCA)/toClient/gulpfile.js
  [10:26:10] Starting 'html'...
  (node:2519) fs: re-evaluating native module sources is not supported. If you are using the graceful-fs module, please update it to a more recent version.
  
  events.js:160
        throw er; // Unhandled 'error' event
        ^
  Error: CSS parse error scripts/vendor.js: Unexpected input
      1 |!function(t,e){"object"==typeof module&amp;&amp;"object"==typeof module.exports?module.exports=t.document?e(t,!0):function(t){if(!t.document)throw new Error("jQuery requires a window with a document");return e(t)}:e(t)}("undefined"!=typeof window?window:this,function(t,e){function i(t){var e="length"in t&amp;&amp;t.length,i=J.type(t);return"function"!==i&amp;&amp;!J.isWindow(t)&amp;&amp;(!(1!==t.nodeType||!e)||("array"===i||0===e||
  </code></pre>
  
  <p>And the code of task 'html':</p>
  
  <pre><code>var $ = require('gulp-load-plugins')();
  
  gulp.task('html', function() {
    var assets = $.useref.assets({searchPath: ['.tmp']});
  
    return gulp.src('app/*.html')
      .pipe(assets)
      .pipe($.if('*.js', $.uglify()))
      .pipe($.if('*.css', $.csso()))
      .pipe(assets.restore())
      .pipe($.useref())
      .pipe($.if('*.html', $.minifyHtml({conditionals: true, loose: true})))
      .pipe(gulp.dest('dist'));
  });
  </code></pre>
  
  <p>I googled a lot but I haven't found a proper answer suitable for me.</p>