To enable clean urls on Ubuntu 14.04+, you must: Enable the Rewrite module on apache: sudo a2enmod rewrite Then, you must edit apache2.conf: sudo nano /etc/apache2/apache2.conf Find the configuration controlling the directory that holds your Drupal code, e.g. /var/www:
<Directory /var/www>
        Options Indexes FollowSymLinks
        AllowOverride None
        AllowOverride All
        Require all granted
</Directory>
Change AllowOverride None to AllowOverride All:
<Directory /var/www>
        Options Indexes FollowSymLinks
        #AllowOverride None (this was the default setting)
        AllowOverride All
        Require all granted
</Directory>
Also, I chose to merely comment out the default setting.