Support » Fixing WordPress » WordPress 3.8 upgrade issue

  • Hi,

    I’ve just upgraded my site to 3.8 and I’ve gotten an error message on my dashboard:

    Warning: call_user_func_array() expects parameter 1 to be a valid callback, function ‘wp_admin_bar_sidebar_toggle’ not found or invalid function name in (…)/public_html/wp-includes/plugin.php on line 507

    The site appears to be working fine but I’d still like to know what to do about this warning.

    Any advice would be greatly appreciated =)



Viewing 12 replies - 1 through 12 (of 12 total)
  • do you still have it? did you disable your plugins ?


    A client of mine updated to 3.8 yesterday and has the same issue with exactly the same error message.

    The error still occurs after deleting all plugins.

    Thanks for any help

    By the way, the site URL is


    I’m getting the same error message as well. Any help would be greatly appreciated.

    I did wonder if it was theme-specific. The site (see above) is currently using a child version of the theme Spun. But then I switched theme to Twenty Thirteen and the error message is still there. So, for me, it appears as if it’s not related to either plugins or theme.

    The source of the error is in wp-includes/plugin.php. The code in that file is the same as the original file from the WP installation i.e. it doesn’t appear as if it’s been corrupted or changed in any way.

    So, I don’t know how to solve this. Maybe the only thing is to completely re-install the site.

    Does anyone else have any suggestions?


    The bug seems to have magically disappeared! No idea why.

    Mine still exists. Did you do anything such as update or remove a plugin that may have helped?

    The error message has reappeared! I’m now even more confused than I was before.

    jtmohatt, as you can see from my previous post, I have no plugins installed. Can I ask if you have any plugins and also which theme are you using? Thanks.

    I am using the Travelify theme and I have several plugins installed. Nothing was wrong until I upgraded to the latest version of WordPress.

    I have the same problem. Am using Avada theme.
    My site is
    Have been looking through lots of online forums but haven’t found any answers. Any help much appreciated!

    Joshaw’s original post states that the error message is on the dashboard. Just to clarify, I am seeing the PHP error message on all pages in the back end (admin) and the front end (website).

    For now, I’ve added a bit of code in wp-config.php which suppresses error messages (as a temporary sticking plaster), so the site doesn’t look messay, but it’s something I want to fix.

    I have updated other sites on the same host to 3.8 and this error doesn’t occur.

    I have no other solutions right now except to wait for the next WP update and hope that fixes it. If that doesn’t work, I guess it’s a complete re-installation and hope that does it.

    Oddly enough the error message has disappeared for me now.

    Maybe it’s a bug wordpress is working on and it’s slightly different for different themes?

    Will post on here if it comes back & if I find a solution elsewhere.

Viewing 12 replies - 1 through 12 (of 12 total)
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