Thread:Project:Support desk/For *computer-novices*: Access denied for user 'user'@'localhost' (using password: YES)/reply (12)

In the horrible evil impossible-for-end users process of resetting the MySQL root password and restarting MySQL, then creating the table and user to tell the mediawiki installer about, the following were immensely useful:

First you need to eliminate the simple stuff but if you can't do that you may need to reset all MySQL permissions, restart MySQL  and then create a new user  and table using a line like this one:

mysql> GRANT ALL ON wiki_name.* to db_user@localhost IDENTIFIED BY 'password';

Then the mediawiki installer should work and create a LocalSettings.php, and god help you if you don't know how to download it and put it in the mediawiki directory (most users couldn't), because it doesn't even offer you the option of putting it there directly (as it certainly should).