Thread:Project:Support desk/Fatal exception of type MWException (2)/reply (5)

No, you should not change LocalisationUpdate.class.php.

Edit your LocalSettings.php file. This file holds a bunch of MediaWiki configuration variables. Add $wgLocalisationUpdateDirectory or $wgCacheDirectory to it and set it to an absolute path to the folder, in which MediaWiki should store the cache files.

E.g.

$wgCacheDirectory = '/path/to/my/wiki/mediawiki-cache';