Magento2 – Fix Error After Grunt Clean

I asked for a bounty, but these seems to be fixed after re run chmod 777 to pub.

Its very hard to develop in magento 2.

Edit:

Open up app/etc/di.xml and find the virtualType name="developerMaterialization" section. In that section you'll find an item name="view_preprocessed" that needs to be modified or deleted. You can modify it by changing the contents from Magento\Framework\App\View\Asset\MaterializationStrategy\Symlink to Magento\Framework\App\View\Asset\MaterializationStrategy\Copy

Delete the files under pub/static to get rid of any existing symlinks. You may want to be careful not to delete the .htaccess file.

grunt exec is esentially a shorthand for clearing the folders var/view_preprocessed, var/generation, var/log/system.log and pub/static and running

php bin/magento dev:source-theme:deploy --type=less --locale=en_US --area=frontend --theme=Package/theme

So before running grunt commands you need to make sure that your comand line php is the same as the server php and that it has access to the database. You get that error because your comand line php does not have access to the database. Also make sure that the user with which you are running grunt has access to delete the var and pub/static volders.