Common issues people run into when installing or configuring Nempra Measure or Nempra Print, and what to do about them. Not covered here? Email hello@nempra.com with your site URL and which plugin/edition you’re using.
“Fatal error: Cannot declare class…” after activating a plugin
This means both Lite and Pro of the same plugin are active at once — Nempra Measure Lite + Pro, or Nempra Print Lite + Pro. Lite and Pro share the same underlying classes, so WordPress can’t load both editions together. Deactivate one before activating the other. Your settings and product data aren’t affected either way, since both editions read the same saved settings.
Nempra Print won’t activate, or shows a legacy-plugin conflict notice
Nempra Print deliberately refuses to start while another supported print-management plugin is still active on the same site, to prevent duplicate hooks or duplicate print jobs. Deactivate the old plugin first, then activate Nempra Print.
Migrating from another print-management plugin — safe staging upgrade
Nempra Print can read a previous supported plugin’s existing settings, print queue and Print Station configuration as a starting point — nothing is deleted. Recommended steps, ideally tried on a staging copy first:
- Back up the database and plugin files.
- Deactivate the old plugin. Don’t delete it yet.
- Install and activate Nempra Print.
- Confirm the former logo, address and printer settings carried over.
- Compare the pickup and delivery counts against your actual WooCommerce orders.
- Test both the printable overviews and one ordinary packing slip.
- Keep automatic printing in test mode until Print Station has been verified end to end.
The measurement calculator doesn’t appear on a product page
Check the following, in order:
- WooCommerce is active — Nempra Measure won’t run without it.
- The product’s Measurement tab has a length range, step size and at least one width saved.
- The product is a Simple product if you’re running Lite — variable products need Nempra Measure Pro.
- Your theme or another plugin isn’t hiding WooCommerce’s default product-page hooks, which the calculator renders into.
Automatic printing (Print Station) isn’t printing new orders
Print Station only works while its browser tab is open and active. Check:
- The Print Station Chrome tab is still open on the always-on computer — closing it (or the computer sleeping) stops polling.
- Chrome’s kiosk-printing mode is enabled — without it, Chrome shows a print confirmation dialog that blocks unattended printing.
- The order status that triggers printing (set in Automatic printing settings) actually matches the status your orders reach — e.g. if it’s set to “Processing” but orders go straight to “Completed”, nothing will queue.
- The computer’s default printer is the one you expect — Print Station always prints to the system default.
A plugin update seems to have reset something
Lite and Pro of the same plugin share one settings store, so switching between them shouldn’t lose anything. If something does look wrong after an update, don’t reconfigure from scratch — email hello@nempra.com with your site URL, the plugin/edition and version, and what changed. It goes straight to the person who wrote the code.
Still stuck?
Email hello@nempra.com with your site URL and which plugin/edition you’re using — there’s no ticket queue, just a direct reply.