I’ve faced a similar issue while working on a WooCommerce-based WordPress site for one of our clients recently. The WYSIWYG editor (TinyMCE) stopped loading properly, especially in the Product Description field, and we got console errors just like yours.

Here are a few things you can try:

1. Disable All Plugins Temporarily

The error Cannot read properties of undefined (reading 'wcBlocksRegistry') is often related to a conflict with the WooCommerce Blocks or another plugin that’s hooking into the editor.

Go to your plugins list and temporarily deactivate all plugins except WooCommerce.

Then check if the editor loads correctly.

If it does, reactivate each plugin one by one to identify the culprit.

2. Switch to a Default Theme

Sometimes the theme might enqueue scripts that interfere with the block editor. Try switching to a default WordPress theme like Twenty Twenty-Four to rule that out.

3. Clear Browser & Site Cache

This issue can also be caused by cached JavaScript files:

Clear your browser cache

If you're using a caching plugin or CDN (like Cloudflare), purge the cache

4. Reinstall the Classic Editor or Disable Gutenberg (Temporarily)

If you're using a classic setup and don't need Gutenberg, install the Classic Editor plugin and see if that resolves the issue. It can bypass block editor conflicts temporarily.

5. Check for Console Errors on Plugin Pages

Go to WooCommerce > Status > Logs to see if anything unusual is logged when the editor fails to load.

6. Update Everything

Ensure:

WordPress core

WooCommerce

All plugins & themes

...are fully updated. These kinds of undefined JavaScript errors are often fixed in plugin updates.

Let me know what worked — happy to help further if you're still stuck. We had a very similar case at our agency (Digital4Design), and in our case, it was a conflict between an outdated Gutenberg add-on and a WooCommerce update.