This article explains how to enable "Parent Paths" if required for your web application.

Plesk 11+

1. On the Websites & Domains tab click on the down arrow by the domain you wish to enable Parent Paths for.
2. Click on Virtual Directories.
3. Click on Directory Properties.
4. Check "Allow to use parent paths".
5. Click OK.

Plesk 10

1. On the Websites & Domains tab, click on "Show Advanced Operations".
2. Click on Virtual Directories.
3. Click on Directory Properties.
4. Check "Allow to use parent paths".
5. Click OK.

Plesk 9 or earlier

1. Click on Home on the left menu.
2. Click on your domain name.
3. Click on Web Directories.
4. Click on Preferences.
5. Check "Allow to use parent paths".
6. Click OK.