Article ID: 119452, created on Jan 2, 2014, last review on May 11, 2014

  • Applies to:
  • Plesk 11.5 for Windows


Upgrading of Parallels Plesk Panel to version 11.5 failed. The following error is shown when enter login and password at https://%plesk_hostname%:8443:

500 Internal server error

Enabling display_errors in %plesk_dir%\admin\php.ini we get:

PHP Warning: include_once(SB\Application\Api.php): failed to open stream: No such file or directory
Line: 95
File: D:\Parallels\Plesk\admin\plib\Loader.php

Where %plesk_dir% is path to Plesk installation directory (e.g., C:\Program Files (x86)\Parallels\Plesk).


Missing files after failed upgrade.


There is no required SB\Application\Api.php file under %plesk_dir%\sb\include\ directory

You can receive missing files from msi package from the autoinstaller repository and place it to required directory.

Use details from KB How to restore files from the plesk.msi package to get instructions for extracting files from msi package.

Alternatively you may copy missing files from the other server with the same OS and Plesk version.

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