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Troubleshooting Missing Invoice Numbers in WooCommerce Orders

16 threads Sep 16, 2025 Plugin → Pdf invoices & packing slips for woocommerce

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If you've noticed that invoice numbers are missing from your WooCommerce orders list, you're not alone. This is a common issue that can be caused by a few different factors. This guide will walk you through the most common reasons and how to fix them.

Why This Happens

The most frequent cause of a missing invoice number is that an invoice document has not yet been created for that specific order. The invoice number is generated and stored at the moment the PDF is first created. If this process hasn't been triggered, the order will appear without a number in the list.

Common Solutions

1. Manually Create the Invoice

If your plugin is not set to automatically create invoices for every order, you will need to generate them manually. To do this:

  1. Navigate to WooCommerce > Orders.
  2. Locate the order missing an invoice number.
  3. Click the Invoice button in the "Actions" column to generate the PDF. The number should now appear.

Note: If you cannot see the "Actions" column, it may be hidden. Click the "Screen Options" tab in the top right corner of your orders list and ensure the "Actions" checkbox is selected.

2. Configure Automatic Invoice Creation

To have invoices (and their numbers) generated automatically, you must configure the plugin to attach them to order emails.

  1. Go to WooCommerce > PDF Invoices > Documents > Invoice.
  2. Find the Attach to: setting.
  3. Select the order email notifications (e.g., "Customer invoice / Order details," "Admin new order") to which the PDF invoice should be attached.
  4. Save your changes.

Now, when one of those emails is sent, an invoice will be automatically created and its number will be saved to the order.

3. Check for HPOS Compatibility

WooCommerce's High-Performance Order Storage (HPOS) can sometimes cause issues. If you have recently enabled HPOS and invoice numbers are not saving, ensure you are using the latest version of the PDF Invoices plugin, as updates often include compatibility fixes for new WooCommerce features.

When to Investigate Further

If the solutions above do not resolve the issue, it's possible a code conflict is preventing the number from saving. To investigate:

  1. Check for any error logs in WooCommerce > Status > Logs (look for logs with the "wpo-wcpdf" or "fatal-errors" prefix).
  2. Temporarily switch to a default WordPress theme (like Storefront) and disable all other plugins except WooCommerce and PDF Invoices to see if the issue resolves itself. If it does, re-enable them one by one to identify the conflicting software.

By following these steps, you should be able to resolve the issue of missing invoice numbers and ensure your records are complete.

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