Posnic Open Source POS

Retail POS Receipt Printer Troubleshooting

When a receipt does not print, protect the transaction before touching cables or retrying payment. Then isolate the application, print queue, connection, printer, and cash-drawer layers one at a time.

Protect the sale first

  1. Confirm whether the sale was completed, declined, cancelled, or still open before pressing Pay or Print again.
  2. Record the bill number, amount, tender, time, terminal, operator, and visible error.
  3. Use reprint only after locating the completed transaction; do not recreate a sale to obtain a receipt.
  4. If the state is uncertain, pause that till and reconcile it before accepting another electronic payment.

Isolate the failing layer

CheckEvidence to collectInterpretation
Printer self-testModel, firmware, paper width, interface, and self-test result.A failed self-test is a printer, power, paper, or hardware problem rather than a POS application problem.
Operating-system test pageSelected printer, driver, port, queue state, and result.A self-test that passes while the OS test fails points to the driver, queue, port, permissions, or connection.
POS test receiptApplication version, configured printer, template, copy count, and exact error.An OS test that passes while only POS printing fails narrows the fault to application configuration or receipt content.
Completed-sale reprintBill identifier and whether one, zero, or multiple copies emerge.This verifies retrieval and rendering without creating another financial transaction.
Cash-drawer kickDrawer wiring, printer port, command settings, and authorized action used.A drawer connected through the printer depends on the printer path; repeated kicks are not a substitute for diagnosis.

Check common failure modes

Recover without creating duplicates

After repair, reprint one known completed bill and label duplicate copies according to shop policy. Reconcile the bill count, payment records, print queue, and any manual receipt log before returning the till to service.

Posnic is offline-first open source POS and Billing Software for retail shops and restaurants. The public Posnic/POS source repository documents implemented hardware interfaces and known evidence boundaries for local and Online/Offline POS deployments.