open browser tools -> network tab ensure that debug developer is not set purge caches refresh any page in moodle *confirm that the calls to theme/yui_combo.php include a timestamp (ignoring the YUI version ones). For example http://banana.local/moodle/sm/theme/yui_combo.php?m/1381393757/core/popuphelp/popuphelp-min.js* open the JS console and run M.cfg.jsrev confirm that the jsrev matches the int in the URL from the previous step browser around Moodle a bit confirm everything is all hunky dory increase debug level to debug_developer refresh the page again confirm that the int in the URL is now -1 confirm that the int in M.cfg.jsrev is also -1