Application can't write to the document root: The directory is not writable by the Web process

Symptoms

• An application fails to write to a site's document root, with an error similar to this one

  The directory is not writable by the Web process

• Trying to enable a WordPress plugin returns an error

  Error: Permission denied

  Error: Invalid URL was requested.

• Opening the application in the browser shows access denied errors (for example, for the Umbraco application)

  Server Error in '/' Application.
  Access to the path 'C:\Inetpub\vhosts\example.com\httpdocs\App_Data\TEMP\PluginCache\umbraco-plugins.WIN-win.hash' is denied.

• The Additional write/modify permissions are disabled in Domains > example.com > Hosting Settings

Cause

The Plesk IIS and IIS application pool users for the site are missing full access rights are not granted.

Resolution

1. Log into Plesk

2. Go to Domains > example.com > Hosting & DNS > Hosting

3. Enable Additional write/modify permissions

4. Press the OK button

To automatically enable this option for new domains, turn on Additional write/modify permissions management in Service Plans > Default > Permissions > Show more permissions.