Is anyone familiar with this error? It is causing TinyMCE to break in my Wordpress theme.

In console it gives me these two errors both seem to originate from wp-admin/post-new.php

Uncaught ReferenceError:switchEditors is not defined

Uncaught TypeError: undefined is not a function /wp-admin/load-scripts.php?c=0&load%5B%5D=hoverIntent,…editor,quickt&load%5B%5D=ags,wplink,wp-fullscreen,media-upload&ver=3.9.1:2

enter image description here

Both the Visual and Smart tabs break, becoming unclickable, and the TinyMCE toolbar disappears.

  • I have this issue, and it looks like the ACF Repeater Field plugin is part of the problem. Haven't been able to resolve it yet though...
    – kdev
    Oct 11, 2014 at 10:17

4 Answers 4


it might me entirely different solution that i am providing but it solved the problem for me.

I followed these steps:

  1. Open the user that is getting error. (Wordpress admin menu > users > your profile)
  2. Changed the setting of "Disable the visual editor when writing" and saved the settings
  3. Again disabled this feature and saved the settings
  4. Boom. my editor is back.

Maybe it could solve someone else problem.



  • Worked for me but i don't understand what actually have happen. Nov 5, 2016 at 4:15
  • Worked for me either.
    – Rüzgar
    May 4, 2017 at 18:21
  • Thats pretty crazy, worked for me too. But oh boi, i dont understand why...
    – Mike
    Oct 24, 2019 at 8:58

You are most probably having a conflict with some plugin or the theme (bad javascript usually). If you got some kind of an adblocker, this might be another reason too, so you'd better check them all and see if it is a browser-sensitive problem.


You can disable concatenation by defining CONCATENATE_SCRIPTS constant to false. In wp-config.php would be fitting:

define('CONCATENATE_SCRIPTS', false);

W3TC shouldn't affect anything on admin side.


This fixed my issue - I added this line to the bottom of wp-config.php and BOOM!

define('CONCATENATE_SCRIPTS', false);

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