How to fix WordPress non-existent changeset UUID ?

It can happen sometimes that you are trying to customize your website from the WordPress live customizer, and you get the following error message in the preview frame : "Non-existent changeset UUID".

This problem usually occurs when there's a mismatch between your actual website URL and the one saved in your WordPress general settings.

To fix this problem :

  1. Connect to your WordPress admin
  2. Navigate to Settings > General in the left panel
  3. Make sure your WordPress Address and your Site Address are exactly the same
  4. Save your changes

That's it, in most of the cases, the error message should have gone now.

If you are still getting the error message, your might want to visit the following forum topic on WP.org :