Fatal Error Upgrading WPML -> Method WPML_Admin_Menu_Item::_

Overview of the Issue

When upgrading WPML, you might encounter the following error:

Catchable fatal error: Method WPML_Admin_Menu_Item::__toString() must return a string value ...

This issue is fixed in WPML Multilingual CMS 4.0.2. Updating solves it on your site, so you only need this workaround if you can’t update yet.

This issue will be fixed in the next WPML release.

Until then, you can apply the following fix.

1. Edit the class-wpml-admin-menu-item.php file found in the ../wp-content/plugins/sitepress-multilingual-cms/classes/admin-menu/ folder.

2. Replace the code found in the function serialize() from this:

To this:

If updating doesn’t fix it, ask a support question and we’ll look into it with you.