GruntJS "bus error grunt watch"

I'm having an error with GruntJS when I try to run a grunt watch. It works fine, until there is a change in the file it is watching, then, it looks something like this:

Running "watch" task
Waiting...[1]    2464 bus error  grunt watch

The number 2464 changes. It seems to be the port that grunt is watching on? But, I'm not sure. Here is my Gruntfile:

module.exports = function (grunt) {
"use strict";

grunt.initConfig({
    pkg: grunt.file.readJSON('package.json'),
    sass: {
        dist: {
            options: {
                style: 'compact'
            },
            files: {
                'css/style.css': 'sass/style.scss',
            }
        }
    },
    watch: {
        files: 'sass/style.scss',
        tasks: ['sass']
    }
});

grunt.loadNpmTasks('grunt-contrib-sass');
grunt.loadNpmTasks('grunt-contrib-watch');

grunt.registerTask('default', ['sass']);
};

Thanks in advance for all the help!