title: Vagrant error: NFS is reporting that your exports file is invalid
body: <p>I am trying to set up the Discourse development environment using these <a href="http://blog.discourse.org/2013/04/discourse-as-your-first-rails-app/" rel="noreferrer">instructions</a>. However when I run Vagrant I get the error:</p>
  
  <blockquote>
    <p>NFS is reporting that your exports file is invalid. Vagrant does
    this check before making any changes to the file. Please correct
    the issues below and execute "vagrant reload":</p>
    
    <p>Can't open /etc/exports</p>
  </blockquote>
  
  <p>I checked, and I don't have an etc/exports folder, so I created one and ran <code>vagrant reload</code>. This got me:</p>
  
  <blockquote>
    <p>/Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/plugins/hosts/bsd/host.rb:146:in <code>read': Is a directory - /etc/exports (Errno::EISDIR)
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/plugins/hosts/bsd/host.rb:146:in</code>nfs_prune'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/plugins/synced_folders/nfs/synced_folder.rb:68:in <code>cleanup'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/builtin/synced_folder_cleanup.rb:24:in</code>block in call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/builtin/synced_folder_cleanup.rb:22:in <code>each_key'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/builtin/synced_folder_cleanup.rb:22:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/plugins/providers/virtualbox/action/prepare_nfs_valid_ids.rb:12:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/builtin/handle_forwarded_port_collisions.rb:118:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/plugins/providers/virtualbox/action/prepare_forwarded_port_collision_params.rb:30:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/builtin/env_set.rb:19:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/builtin/provision.rb:52:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/plugins/providers/virtualbox/action/clear_forwarded_ports.rb:13:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/plugins/providers/virtualbox/action/set_name.rb:19:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/plugins/providers/virtualbox/action/clean_machine_folder.rb:17:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/plugins/providers/virtualbox/action/check_accessible.rb:18:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:95:in</code>block in finalize_action'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/builder.rb:116:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/runner.rb:69:in</code>block in run'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/util/busy.rb:19:in <code>busy'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/runner.rb:69:in</code>run'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/builtin/call.rb:51:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:95:in <code>block in finalize_action'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/builder.rb:116:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/runner.rb:69:in <code>block in run'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/util/busy.rb:19:in</code>busy'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/runner.rb:69:in <code>run'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/builtin/call.rb:51:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:95:in</code>block in finalize_action'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/builder.rb:116:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/runner.rb:69:in</code>block in run'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/util/busy.rb:19:in <code>busy'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/runner.rb:69:in</code>run'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/builtin/call.rb:51:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/builtin/config_validate.rb:25:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/plugins/providers/virtualbox/action/check_virtualbox.rb:17:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/builtin/call.rb:57:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/plugins/providers/virtualbox/action/check_virtualbox.rb:17:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/builtin/config_validate.rb:25:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:95:in <code>block in finalize_action'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/builder.rb:116:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/runner.rb:69:in <code>block in run'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/util/busy.rb:19:in</code>busy'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/runner.rb:69:in <code>run'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/builtin/call.rb:51:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/plugins/providers/virtualbox/action/check_virtualbox.rb:17:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/warden.rb:34:in <code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/builder.rb:116:in</code>call'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/runner.rb:69:in <code>block in run'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/util/busy.rb:19:in</code>busy'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/action/runner.rb:69:in <code>run'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/machine.rb:147:in</code>action'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/plugins/commands/reload/command.rb:37:in <code>block in execute'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/plugin/v2/command.rb:193:in</code>block in with_target_vms'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/plugin/v2/command.rb:191:in <code>each'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/plugin/v2/command.rb:191:in</code>with_target_vms'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/plugins/commands/reload/command.rb:36:in <code>execute'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/cli.rb:38:in</code>execute'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/lib/vagrant/environment.rb:484:in <code>cli'
        from /Applications/Vagrant/embedded/gems/gems/vagrant-1.4.1/bin/vagrant:127:in</code>'
        from /Applications/Vagrant/bin/../embedded/gems/bin/vagrant:23:in <code>load'
        from /Applications/Vagrant/bin/../embedded/gems/bin/vagrant:23:in</code>'</p>
  </blockquote>
  
  <p>I am on a Mac (OS X 10.6.8). How do I fix this? I tried searching for the original error message, and all I found was a few repositories containing the Vagrant source code that throws it.</p>