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Troubleshooting Common Broken Link Checker Installation and Fatal Errors

26 threads Sep 11, 2025 Plugin → Broken link checker

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Users of the Broken Link Checker plugin sometimes encounter errors during installation or while the plugin is running. These issues can range from database errors to fatal PHP crashes that make a site's admin area inaccessible. Based on community reports, this guide outlines the most common causes and their solutions.

Common Error: Installation Fails or Settings Are Missing

A frequent issue is an installation that fails with a message stating the plugin could not load settings from the wsblc_options option, which doesn't exist in the wp_options database table. This often happens after migrating a site to a new server or host.

Why This Happens:

This error typically indicates that the plugin's initial setup script did not complete successfully. The database table that stores the plugin's configuration is missing. Conflicts with other plugins, like caching or security tools (e.g., WordFence, W3 Total Cache), can sometimes interrupt the installation process.

How to Fix It:

  1. Perform a Clean Reinstall: The first step is to deactivate the Broken Link Checker plugin and then delete it completely from your WordPress plugins page.
  2. Check for Conflicts: Before reinstalling, temporarily deactivate any caching, security, or optimization plugins. These can sometimes interfere with the creation of database tables.
  3. Reinstall the Plugin: Install and activate Broken Link Checker again. This should trigger the full installation routine and create the necessary database tables and options.
  4. Check PHP Version: Ensure your server is running a supported version of PHP (e.g., 7.4 or higher). An outdated PHP version can cause unexpected errors.

Common Error: Fatal PHP Errors After an Update

Another common problem is a "Fatal error" that appears immediately after updating the plugin, often making the WordPress admin area inaccessible. Errors like Class "WPMUDEV_BLCCoreLoader" not found or Parse error: syntax error, unexpected '[' fall into this category.

Why This Happens:

These errors are usually caused by an incomplete or corrupted plugin update. If all plugin files are not successfully copied to your server during the automatic update process, it can lead to missing classes or syntax errors. The latter error (unexpected '[') can also occur if the server is running an very old version of PHP that doesn't support modern syntax.

How to Fix It:

  1. Re-upload the Plugin via FTP/SFTP: This is the most reliable fix. Access your site's server via FTP/SFTP, navigate to the wp-content/plugins/ directory, and delete the entire broken-link-checker folder. Then, upload a fresh, freshly downloaded ZIP file of the plugin from the WordPress.org repository and extract it.
  2. Manual Update: If you cannot access your admin area, manually replacing the plugin files as described above will often resolve the immediate fatal error and restore access.
  3. Verify PHP Version: Confirm your server meets the plugin's minimum PHP requirement. Updating your PHP version to 7.4 or higher can resolve syntax-related errors.

Common Error: Database Collation and Table Issues

Errors mentioning "Illegal mix of collations" or an "Incorrect file format' for a table like wp_blc_instances point to a database issue.

Why This Happens:

WordPress databases can use different character sets and collations. If your database tables were created with different collations (e.g., utf8mb4_unicode_ci vs. utf8mb4_unicode_520_ci), MySQL can refuse to compare them in a single query. The "incorrect file format" error suggests a specific database table may be corrupted.

How to Fix It:

  1. Repair Database Tables: You can use a plugin like "WP-DBManager" or your hosting provider's database tool (e.g., phpMyAdmin) to check and repair your WordPress database tables. This can fix corruption issues.
  2. Standardize Collation: For advanced users, using phpMyAdmin to change the collation of the plugin's tables to match the rest of your WordPress database can resolve the "illegal mix" error. It is highly recommended to create a full database backup before attempting this.

General Troubleshooting Tips

  • Enable WP_DEBUG: Temporarily enabling WordPress debugging can provide more detailed error messages, making it easier to identify the root cause.
  • Check Error Logs: Your web hosting provider often has server error logs that can contain more information than what is displayed on screen. Contact your host for help accessing these logs.
  • Conflict Test: If errors occur during specific actions (like quick edits), try temporarily switching to a default WordPress theme (e.g., Twenty Twenty-Four) and deactivating all other plugins to see if the issue resolves. If it does, reactivate them one by one to find the conflict.

If you continue to experience issues, the official WordPress support forums for Broken Link Checker are an active community where you can search for your specific error or start a new thread for help.

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