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Troubleshooting Common Smush Bulk Smush Issues: Stuck Progress, Missing Files, and Loops

40 threads Sep 7, 2025 Plugin → Smush image optimization – optimize images | compress & lazy load images | convert webp & avif | image cdn

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Many WordPress users rely on the Smush Image Optimization plugin to handle their image compression. However, a frequent point of confusion and frustration occurs when the Bulk Smush feature doesn't work as expected. Based on community reports, this article outlines the most common Bulk Smush problems and their potential solutions.

Common Bulk Smush Problems

  • Bulk Smush gets stuck at 0% or a certain percentage and does not progress.
  • The process completes but the image count resets, creating an endless loop.
  • Errors appear stating "file not found," "could not find image," or "couldn't process image due to bad headers."
  • The Bulk Smush button is missing, grayed out, or does nothing when clicked.

Why These Issues Happen

These problems are rarely due to a single cause. The most common underlying issues include:

  • Missing Image Files: The plugin's database record for an image exists, but the actual file (or one of its thumbnails) is missing from the server.
  • Server Configuration: Server settings like low PHP memory limits, short max execution times, or restrictive firewalls can halt the process.
  • Plugin or Theme Conflicts: Another plugin or your theme might be interfering with Smush's functionality.
  • Problematic Image Files: Corrupted images or files with incorrect headers can cause the process to fail on that specific image.
  • Caching: Server-level or object caching can sometimes cause the interface to display outdated information.

How to Troubleshoot and Fix Bulk Smush Issues

1. Check for Console Errors

If the process is stuck, the browser's console can often reveal underlying JavaScript errors.

  1. Open your browser's developer tools (usually F12).
  2. Navigate to the "Console" tab.
  3. Start the Bulk Smush process and watch for any red error messages.
  4. These errors can provide a direct clue about what is breaking.

2. Identify and Fix Missing Images

A very common cause is a missing thumbnail for an image. The database says the thumbnail should exist, but the file is not on the server. To fix this:

  1. Use a plugin like "Regenerate Thumbnails" to recreate all missing image sizes.
  2. If only a few images are affected, you can try deleting and re-uploading them manually.

3. Perform a Conflict Test

This is a fundamental troubleshooting step to rule out conflicts with other code.

  1. Backup your site before proceeding.
  2. Deactivate all plugins except Smush.
  3. Switch your theme to a default WordPress theme (e.g., Twenty Twenty-Four).
  4. Check if Bulk Smush now works correctly.
  5. If it does, reactivate your plugins and theme one by one, testing after each activation, to identify the culprit.

4. Adjust Server Configuration

Ensure your server environment meets the demands of bulk processing. The Smush team often recommends the following settings in your wp-config.php file or via your hosting control panel:

  • define('WP_MEMORY_LIMIT', '256M');
  • define('MAX_EXECUTION_TIME', 300);

You can also try adding this specific definition for Smush to change how it scans for images:

define( 'WP_SMUSH_SCAN_SLICE_SIZE', 250 );

5. Check File Permissions and Firewalls

Ensure Smush can access your image files. Verify that file permissions on your wp-content/uploads/ directory are correct (usually 755 for folders and 644 for files). If you are using a firewall, you may need to allow the IP addresses used by the Smush service.

6. Clear Caches

If the plugin interface shows incorrect counts or seems to be looping, clear all levels of cache:

  • Clear your WordPress caching plugin's cache.
  • Clear any server-level or object cache (e.g., Redis, Memcached).
  • Clear your CDN cache (if used).

When to Suspect a Specific Image

If the process consistently fails on a specific image ID (often visible in a console error), that image is likely corrupt. Open that specific attachment in your Media Library. If it fails to load or appears broken, you will need to delete and re-upload it.

By methodically working through these steps, you can usually identify and resolve the issue preventing Bulk Smush from working correctly on your WordPress site.

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