WordPress Custom CSS Editor Not Working (Getting JSON_PARSE_ERROR)

Note:

i deactivated ALL plugins and even changed the theme to wordpress’ default theme and I still get the same error.

I’m having the same issue

Apparently there is a corrupted customize_changeset post in the DB. I presume you have an existing draft saved. Not sure how it would have been corrupted, but to start over you should be able to open the publish settings panel (via the gear icon) in the Customizer and hit the link to trash the drafted current changes.

I will try that and let you know how it goes.

That fixed the issue @westonruter.

Thanks

If you can figure out a way to reproduce the problem that would be ideal so we can fix the issue in core.

Here’s where that error is returned: https://github.com/WordPress/wordpress-develop/blob/1c4f57f425fed9bec01e558d22d1fb751881e347/src/wp-includes/class-wp-customize-manager.php#L1120

Next time it happens, find out what the contents are for the post_content of the customize_changeset post.

• This reply was modified 6 years, 10 months ago by Weston Ruter.

Not sure I can ‘cos I have already deleted the changedset.