I've just upgraded to 1.5.9. Following this I upgraded UI.X to 1.5.9 and when merging a particular template, I got a MySQL server has gone away error each time. I emptied much of the template and managed to save it, then decided that I would rebuild the master data just in case. However, this won't complete as each time I get this error: Code: Server Error Error while sending QUERY packet. PID=XXXXX XenForo_Application::handlePhpError() mysqli->rollback() in Zend/Db/Adapter/Mysqli.php at line 444 Zend_Db_Adapter_Mysqli->_rollBack() in Zend/Db/Adapter/Abstract.php at line 523 Zend_Db_Adapter_Abstract->rollBack() in XenForo/Db.php at line 131 XenForo_Db::rollback() in XenForo/Db.php at line 155 XenForo_Db::rollbackAll() in XenForo/Model/Deferred.php at line 304 XenForo_Model_Deferred->runDeferred() in XenForo/Model/Deferred.php at line 429 XenForo_Model_Deferred->_runInternal() in XenForo/Model/Deferred.php at line 355 XenForo_Model_Deferred->runByUniqueKey() in XenForo/Install/Controller/Abstract.php at line 34 XenForo_Install_Controller_Abstract->_manualDeferredRunner() in XenForo/Install/Controller/Upgrade.php at line 221 XenForo_Install_Controller_Upgrade->actionRunDeferred() in XenForo/FrontController.php at line 351 XenForo_FrontController->dispatch() in XenForo/FrontController.php at line 134 XenForo_FrontController->run() in /.../install/index.php at line 18 (I've removed the actual PID and edited the path in the final line). If I refresh the page at this point I arrive at the Upgrade complete screen. However each time I try to rebuild the master data I get the same error. This is currently on my test site but I'd like to get this issue resolved (both this error and the MySQL server has gone away when merging a template - never ever had this before) before upgrading my live site.