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[MPG] Encountering 404 – Page Not Found ​

The Multiple Pages Generator is a WordPress plugin for the bulk creation of pages, even unlimited pages.

However, if your URL is showing as a 404 Error – Page Not Found, here’s a checklist to fix it:

1. Sometimes it happens after upgrading to the new version, so deactivate the plugin (without cancelling the license, if any) and activate it again

2. Make sure that the MPG plugin is properly installed; the CSV source file is loaded, and the template is properly set.

3. Check if the requested URL doesn’t belong to an existing page, especially in the trash folder.

4. Check if the requested URL is identical to the one included in the data file uploaded to the MPG plugin.

5. Make sure to disable any custom 404-page plugins. Sometimes they check the page URL in the database before MPG does and return as 404.

6.  Also, check for these most common problems that cause 404 Error:

a.Unsupported characters in a column used as a shortcode for URL generation.

b.Use of “Plain” permalink structure under Settings > Permalinks.

c. Conflict with another plugin

7. If your data source includes a created_date column (a Pro feature), check the value for the missing URL. MPG treats a future created_date as a scheduled publish date, so that page returns a 404 error until the date and time arrive.

MPG supports multi-sites and multi-language setups, though specific plugins might not be supported.

In this article

Caching/Optimization Purges (Uploaded Files Only) ​

If your MPG project uses an uploaded CSV or Excel file as its data source (rather than a Google Sheets URL), 404 errors can appear after caching or database-optimization routines run on your site. This happens because these operations can delete or clear MPG's folder inside your WordPress uploads directory (or its associated WordPress transients), which removes the index.json file that MPG relies on to serve the generated pages.

Note: Projects connected to a Google Sheets URL recover on their own because MPG re-fetches the data automatically. Uploaded-file projects can also rebuild their missing index data when a generated URL is requested, but only while the uploaded source file is still on the server. If the purge removed the source file too, or the 404s keep coming back after each cleanup, the fix has to be applied at the caching/optimization layer.

Why this happens ​

Caching plugins and optimization tools often perform aggressive cleanup routines that may:

  • Purge MPG's folder in your uploads directory or its contents as part of a media/upload cleanup.
  • Flush WordPress transients that MPG uses to track uploaded project data.

MPG stores its files in an mpg folder inside your WordPress uploads directory, usually wp-content/uploads/mpg/. If your site uses a custom uploads location, the folder follows it. Each project lives under mpg/project-<project-id>/, with the active build's index.json located at project-<project-id>/builds/<build-id>/index.json (the active build is tracked by current-build.json). When that index.json file is removed, MPG can no longer map incoming URLs to generated pages, causing a 404 for every visitor.

Re-uploading the file restores pages temporarily, but the 404s will recur the next time the cleanup runs.

How to diagnose ​

Using a file manager (e.g., your host's File Manager or an FTP client), navigate to:

wp-content/uploads/mpg/project-<your-project-id>/builds/<build-id>/

Check whether index.json is present. If the file is missing, a recent caching or optimization purge is the likely cause.

How to fix ​

Exclude MPG's folder in your uploads directory, usually wp-content/uploads/mpg/, from all cleanup routines in your caching and optimization plugins:

WP Rocket

  1. Go to WP Rocket → Settings → File Optimization (and/or Media).
  2. Add wp-content/uploads/mpg to any exclusion lists for file cleanup or CDN.
  3. Go to WP Rocket → Settings → Advanced Rules and add wp-content/uploads/mpg/ to the Never Cache URL(s) field if applicable.

WP-Optimize

  1. Go to WP-Optimize → Database and review the Transients cleanup options.
  2. Disable automatic transient deletion or configure it to exclude MPG transients.
  3. Under WP-Optimize → Cache → Exclusions, add wp-content/uploads/mpg/ to ensure the directory is not purged.

Other caching or optimization plugins Look for settings labelled "Excluded files/directories", "Safe-list", or "Do not delete" and add wp-content/uploads/mpg/ there.

After applying the exclusion, re-upload your CSV/Excel file once to regenerate index.json, and the 404 errors should stop recurring.

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