After installing the latest version of Joomla you may sometimes notice the below error in the “admin” section.
An error occured
This happens because of the incorrect/low MySQL “sort_buffer_size”, to fix this edit the “my.cnf” file
Add the below line to the end of the file
sort_buffer_size = 1M
Restart the MySQL server by executing
service mysqld restart
service mysql restart
Now refresh the Joomla admin section and the error will not be displayed anymore.