Upgrading New Installation Prompt

From WHMCS Documentation

Encountering a no existing installation was detected message when upgrading an existing WHMCS installation to a newer version indicates a problem which must be corrected before proceeding with the upgrade.

Important
Do not continue with the upgrade process until the advice on this page has been followed

The upgrade process determines the presence of an existing installation by looking for the configuration.php file in the root WHMCS installation directory (the same directory which contains init.php, index.php and clientarea.php). Therefore ensure the file exists and contains the connection details to your MySQL database, the contents should look something like this:

<?php
$license = 'WHMCS-xxxxxxxxx';
$db_host = 'localhost';
$db_username = 'root';
$db_password = 'xxxxxxxx';
$db_name = 'whmcs';
$cc_encryption_hash = 'xxxxxxxxxxxxxxxxxxxxxxxxxx';

The upgrade process must be able to read the contents of the configuration.php file. Ensure the permissions and ownership of the file are set appropriately. We suggest CHMOD 444.

Once the existence, contents and permissions of the configuration.php file have been corrected, refresh the install.php page and confirm the message stating an upgrade will be performed is displayed before proceeding. Should the "no existing installation was detected" message still be displayed, please contact technical support.