BugWP logo BugWP
Back to Community
Home / Community / Plugin → Speed optimizer – the all-in-one performance-boosting plugin

Troubleshooting Common Speed Optimizer Plugin Deletion and Critical Errors

18 threads Sep 16, 2025 Plugin → Speed optimizer – the all-in-one performance-boosting plugin

Content

Many WordPress users encounter frustrating issues when trying to deactivate or delete the 'Speed Optimizer – The All-In-One Performance-Boosting Plugin'. This guide covers the most common problems and provides step-by-step solutions to resolve them.

Common Problems and Their Causes

Based on community reports, these are the most frequent issues:

  • Deletion Fails with Critical Error: Users see "Deletion failed: There has been a critical error on this website" when trying to remove the plugin.
  • 500 Internal Server Error: The site crashes with a 500 error after activation or during use.
  • Admin Login Issues: Login pages crash or redirect improperly, especially on non-SiteGround hosting.
  • Plugin Leaves Residual Files: Caching persists even after plugin deletion, causing users to see old versions of pages.
  • Function Disable Errors: Users cannot disable specific features like "Remove Query Strings" or "Disable Emojis".

These problems often occur because the plugin modifies critical files like .htaccess, leaves behind cache files, or has compatibility issues with other plugins, themes, or specific hosting environments (especially non-SiteGround servers).

Step-by-Step Solutions

1. For Critical Errors During Deletion

If you see a "critical error" when trying to delete the plugin:

  1. Enable WordPress Debugging: Add these lines to your wp-config.php file to get detailed error information: 
    define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true );
define( 'WP_DEBUG_DISPLAY', false );
  2. Attempt to delete the plugin again and check the wp-content/debug.log file for specific error messages.
  3. Common errors involve functions like exec() being disabled on the server or array key issues in the plugin code.

2. Manual Plugin Removal

If standard deletion fails, manually remove all plugin components:

  1. Delete Plugin Files: Use FTP or your hosting file manager to remove these directories:
    • wp-content/plugins/sg-cachepress/
    • wp-content/uploads/siteground-optimizer-assets/
    • wp-content/cache/sgo-cache/
  2. Clean Database: Use a database management tool (like phpMyAdmin) to remove any database records containing the term siteground_optimizer.
  3. Restore .htaccess: The plugin adds rules to your .htaccess file. Open the file and remove any rules preceded by comments mentioning "SG-Optimizer" or "SiteGround Speed Optimizer".
  4. Disable Caching: Ensure define( 'WP_CACHE', false ); is set in your wp-config.php file.

3. Fix 500 Internal Server Errors

If your site shows a 500 error after plugin activation:

  1. Check .htaccess: Rename your .htaccess file to .htaccess_old to see if the error resolves. If it does, the plugin's rewrite rules may conflict with your server configuration.
  2. Check PHP Error Logs: Contact your hosting provider for access to PHP error logs, which often contain more detailed information about 500 errors.
  3. Plugin Conflicts: Deactivate all other plugins and switch to a default theme (like Twenty Twenty-Four) before reactivating Speed Optimizer to check for conflicts.

4. Resolve Caching Issues After Removal

If your site continues to show cached versions after plugin removal:

  1. Clear your browser cache and any server-side caching mechanisms provided by your host.
  2. Check if your hosting provider (especially SiteGround) has server-level caching enabled in your account dashboard that needs to be disabled separately.
  3. Consider using a cache-purge plugin temporarily to ensure all residual cache is cleared.

Prevention Tips

  • Always create a full backup of your site (files and database) before installing or removing optimization plugins.
  • Check plugin compatibility with your WordPress version, PHP version, and other installed plugins.
  • If you're not using SiteGround hosting, be aware that some features may not work correctly on all server environments.

While the 'Speed Optimizer – The All-In-One Performance-Boosting Plugin' team works to address these issues, these troubleshooting steps should help resolve most common problems encountered by users.

Related Support Threads Support