Uncaught TypeError: Cannot call method 'switchto' of undefined
Clearing the cache also resulted in a notification within the WordPress CMS
For those running into the same issue this can be fixed by adding the following line to your wp-config.php file…
define( 'CONCATENATE_SCRIPTS', false );
While this might solve this issue the real problem probably lies somewhere else. Most likely there is a plugin ‘conflicting’. You can simply find out if this is the case by disabling all plugins and see if this fixes the problem. Don’t forget to remove the define mentioned above if you’re going on this debugging route and back up your database!