title: "Warning: The "path" argument must be of type string Use --force to continue."
body: <p>Received this error when I attempt to run grunt on a new dev install: </p>
  
  <blockquote>
    <p><code>"Warning: The "path" argument must be of type string Use --force to continue."</code></p>
  </blockquote>
  
  <p>Here's what my <code>gruntfile.js</code> looks like. I've ruled out an incorrect path, what else might cause that and how do I identity where the bad path is located?</p>
  
  <pre class="lang-js prettyprint-override"><code>module.exports = function (grunt) {
  'use strict';
  
  // Load all grunt tasks
  require( 'matchdep' ).filterDev( 'grunt-*' ).forEach( grunt.loadNpmTasks );
  
  // Project configuration
  grunt.initConfig( {
      pkg   : grunt.file.readJSON( 'package.json' ),
      concat: {
          options     : {
              stripBanners: true,
              banner      : '/*! &lt;%= pkg.title %&gt; - v&lt;%= pkg.version %&gt; - &lt;%= grunt.template.today("yyyy-mm-dd") %&gt;\n' +
                  ' * &lt;%= pkg.homepage %&gt;\n' +
                  ' * Copyright (c) &lt;%= grunt.template.today("yyyy") %&gt;;' +
                  ' * Licensed GPLv2+' +
                  ' */\n'
          },
          jdrf_promise: {
              src : [
                  'assets/js/src/jdrf_promise.js',
                  'assets/js/src/promise_map.js'
              ],
              dest: 'assets/js/jdrf_promise.js'
          }
      },
      jshint: {
          browser: {
              options: {
                  jshintrc: '.jshintrc',
                  reporter: require( 'jshint-stylish' )
              },
              src    : [
                  'assets/js/src/*.js'
              ]
  
          }
      },
      uglify: {
          all: {
              files  : {
                  'assets/js/jdrf_promise.min.js': ['assets/js/jdrf_promise.js'],
                  'assets/js/promise_map.min.js' : ['assets/js/promise_map.js']
              },
              options: {
                  banner    : '/*! &lt;%= pkg.title %&gt; - v&lt;%= pkg.version %&gt; - &lt;%= grunt.template.today("yyyy-mm-dd") %&gt;\n' +
                      ' * &lt;%= pkg.homepage %&gt;\n' +
                      ' * Copyright (c) &lt;%= grunt.template.today("yyyy") %&gt;;' +
                      ' * Licensed GPLv2+' +
                      ' */\n',
                  mangle    : false,
                  beautify  : false,
                  semicolons: true
              }
          }
      },
      test  : {
          files: ['assets/js/test/**/*.js']
      },
      compass: {
          dev: {
              options: {
                  sassDir    : ['assets/css/sass'],
                  cssDir     : ['assets/css'],
                  environment: 'development',
                  outputStyle: 'expanded'
              }
          },
          dist: {
              options: {
                  sassDir: 'assets/css/sass',
                  cssDir : 'assets/css/'
              }
          }
      },
      cssmin : {
          options: {
              banner: '/*! &lt;%= pkg.title %&gt; - v&lt;%= pkg.version %&gt; - &lt;%= grunt.template.today("yyyy-mm-dd") %&gt;\n' +
                  ' * &lt;%= pkg.homepage %&gt;\n' +
                  ' * Copyright (c) &lt;%= grunt.template.today("yyyy") %&gt;;' +
                  ' * Licensed GPLv2+' +
                  ' */\n'
          },
          minify : {
              expand: true,
  
              cwd: 'assets/css',
              src: ['jdrf_promise.css'],
  
              dest: 'assets/css',
              ext : '.min.css'
          }
      },
      watch  : {
          compass: {
              files: ['assets/css/sass/*.scss', 'assets/css/sass/*/*.scss'],
              tasks: ['compass:dev']
          },
          styles: {
              files: ['assets/css/jdrf_promise.css'],
              tasks: ['cssmin']
          },
          scripts: {
              files  : ['assets/js/src/**/*.js', 'assets/js/vendor/**/*.js'],
              tasks  : ['jshint', 'concat', 'uglify'],
              options: {
                  debounceDelay: 500
              }
          }
      }
  } );
  
  //Dependent plugins
  grunt.loadNpmTasks( 'grunt-contrib-compass' );
  grunt.loadNpmTasks( 'grunt-contrib-watch' );
  
  // Default task.,
  grunt.registerTask( 'default', ['jshint', 'concat', 'uglify', 'compass:dev', 'cssmin' ] );
  
  grunt.util.linefeed = '\n';
  };
  </code></pre>