Troubleshooting: Why Your Better Search Replace Dry Run Shows No Results

Many users of the Better Search Replace plugin report a common and frustrating issue: they initiate a dry run, the process appears to complete, but no results or report is displayed. The page may simply refresh, leaving you wondering what happened. This guide will explain the likely causes and walk you through the most effective troubleshooting steps to resolve this problem.

Why Does This Happen?

Based on community reports, the dry run failing to show results is rarely a single-issue problem. Instead, it's typically caused by one of the following underlying conditions:

• PHP Errors or Warnings: A silent PHP error during the process can prevent the results page from rendering correctly, causing a blank screen or a page refresh.
• Plugin or Theme Conflict: Another plugin or your active theme might be causing a JavaScript conflict or a PHP error that interferes with Better Search Replace's ability to display its results.
• Execution Time Limits: On very large databases with hundreds of tables, the script might be hitting your server's maximum execution time (timeout) before it can finalize and display the report.
• Memory Limits: The search process can be memory-intensive. If PHP runs out of allocated memory, it will halt execution, often without showing an error.

Step-by-Step Troubleshooting

Follow these steps to identify and fix the root cause of your missing dry run results.

Step 1: Enable Debugging to Reveal Hidden Errors

The first and most crucial step is to make hidden PHP errors visible by enabling WordPress debugging. This will often reveal the exact error causing the blank page.

1. Connect to your website using FTP or your web host's file manager.
2. Locate and edit the wp-config.php file in your site's root directory.
3. Find the line that says: define( 'WP_DEBUG', false );
4. Replace it with the following lines:

   define('WP_DEBUG', true);
   define('WP_DEBUG_LOG', true);
   define('WP_DEBUG_DISPLAY', false);

5. Save the file and upload it back to your server.
6. Run another dry run in Better Search Replace.

This configuration will log any errors to a file called debug.log in your /wp-content/ directory. Check this log file for any errors related to the plugin or PHP limits after running the dry run.

Step 2: Check for Conflicts

A quick way to rule out conflicts with other plugins or your theme is to perform a conflict test.

1. Temporarily switch your WordPress theme to a default theme like Twenty Twenty-Four.
2. Deactivate all other plugins except for Better Search Replace.
3. Run another dry run. If the results now appear, you know a conflict was the cause.
4. Reactivate your plugins one by one, testing the dry run after each one, until you find the culprit.
5. Finally, switch back to your original theme to test it as well.

Step 3: Adjust Plugin and Server Settings

If the issue is related to resource limits, you can try a few adjustments.

• Reduce Max Page Size: Within the Better Search Replace settings, try reducing the "Max Page Size" value. A lower value processes data in smaller chunks, which can help avoid timeouts and memory issues on large databases.
• Increase PHP Limits: If your debug log shows memory or time limit errors, contact your web host and ask them to temporarily increase your PHP memory_limit, max_execution_time, and max_input_vars for troubleshooting.

Summary

The issue of a dry run completing without showing results is almost always due to a hidden PHP error, a conflict, or a server resource limit. The troubleshooting path recommended by the Better Search Replace team and confirmed by the community is to first enable debugging to reveal errors, then perform a conflict test. For very large sites, adjusting the plugin's page size or consulting with your host about increasing PHP limits may be necessary.