Mass delete error

I’m having a weird issue with mass delete accounts. I’m getting the following error:

PHP Fatal error: Uncaught Error: Call to undefined function sugar_unserialize() in /var/www/html/SuiteCRM/include/MVC/Controller/SugarController.php:665

Anybody here knows what this could be. Google doesn’t help, it seems I’m the only one with this problem.

Please can you provide more information on your server environment and SuiteCRM installation with versions etc.