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Troubleshooting Common Classic Editor Activation and Conflict Issues

41 threads Sep 7, 2025 Plugin → Classic editor

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Many WordPress users rely on the Classic Editor plugin to maintain a familiar writing experience. However, like any plugin, it can sometimes run into problems. Based on community reports, here are the most common issues and how to resolve them.

1. Plugin Won't Activate or Deactivates Itself

The Problem: You click "Activate," the page refreshes, but the plugin remains deactivated. In some cases, it may even deactivate itself after saving a post draft.

Why It Happens: This is almost always caused by a conflict with another plugin or a specific hosting environment. The high number of active plugins, particularly those that also affect the admin area or post editor, increases the chance of a conflict.

How to Fix It:

  1. Conflict Test: The most reliable way to find the culprit is to deactivate all other plugins. If Classic Editor activates successfully, reactivate your other plugins one by one to identify which one causes the conflict.
  2. Check Hosting Rules: Some managed hosting providers have custom rules that can interfere. If the conflict test doesn't work, contact your host's support and ask if any WordPress-specific optimizations or security rules might be blocking plugin functionality.

2. JavaScript Errors Breaking the Editor Interface

The Problem: After a WordPress core update (e.g., to 5.6), the Classic Editor interface appears broken. Functions like adding tags or changing the post date don't work, and the browser's console shows errors like Uncaught TypeError: this._addClass is not a function.

Why It Happens: WordPress core updates can change the included JavaScript libraries. If another plugin or your theme is loading an outdated or duplicate version of a library like jQuery UI, it creates a conflict that breaks scripts the Classic Editor relies on.

How to Fix It:

  1. Check for Errors: Open your browser's developer console (F12) while on the editor screen to see if any red error messages are present.
  2. Update Everything: Ensure your WordPress core, the Classic Editor plugin, your theme, and all other plugins are updated to their latest versions. Developers often release compatibility patches after major WordPress releases.
  3. Conflict Test: Again, deactivate other plugins and switch to a default theme (like Twenty Twenty-One) to see if the problem resolves itself. This will pinpoint the source of the problematic script.

3. Conflicts with Other Plugins (Yoast SEO, Jetpack)

The Problem: After activating Classic Editor, a specific feature from another plugin stops working. Common reports include Yoast SEO meta boxes becoming unclickable or Jetpack's Publicize feature sharing posts incorrectly.

Why It Happens: Both plugins are trying to modify the same part of the WordPress admin (the post editor). A slight incompatibility in their code can cause one to override the other.

How to Fix It:

  1. Identify the Conflict: Confirm the issue is caused by Classic Editor by deactivating it. If the other plugin's feature starts working again, you've confirmed the conflict.
  2. Seek Updates: Check for updates for both plugins. Developers for popular plugins like Yoast SEO and Jetpack are usually aware of these conflicts and release fixes.
  3. Report the Issue: If the problem persists with the latest versions, report the specific conflict to the support forums for the other plugin (e.g., Yoast or Jetpack). Providing details helps their developers create a patch.

4. Missing Meta Boxes or Editor Features

The Problem: Familiar editor features, like the Excerpt meta box or custom fields, are missing from the screen.

Why It Happens: This is usually not a direct bug in the Classic Editor but a matter of screen layout. The Classic Editor restores the old editing screen, but your user profile or screen options might be configured to hide certain boxes.

How to Fix It:

  1. While on the post edit screen, click the "Screen Options" tab in the top right corner.
  2. Ensure the checkboxes for the missing features (e.g., "Excerpt," "Custom Fields") are ticked.
  3. Also, drag and drop the meta boxes on the screen to your preferred layout.

By following these steps, you can resolve the majority of issues encountered with the Classic Editor plugin. The most powerful tool in your troubleshooting toolkit is the simple process of deactivating other plugins to isolate a conflict.

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