What this means

Error 79 means your printer suffered a firmware crash. The operating system hit an instruction it cannot process and stopped to protect itself. This usually happens because of a corrupt print job from your computer, a bad print driver causing communication failures, or outdated firmware overwhelmed by network traffic.

It looks like permanent hardware failure, but the printer is not broken beyond repair. Its software is simply trapped in a loop or overwhelmed by bad data. Clear the incoming data queue and restart the machine to resolve the issue.

Common causes

  • Corrupt print job stuck in the print queue
  • Outdated printer firmware
  • Incompatible or corrupt print driver
  • Network traffic flooding the printer
  • Corrupted network settings
  • Failing or incompatible formatter board
  • Faulty optional RAM or accessory card

What to check first

  1. 1Note whether the error happens immediately on startup or only when a specific computer sends a job
  2. 2Check if the printer is connected via network or USB
  3. 3Observe if the printer can complete a test page when disconnected from the network

Step-by-step fix

  1. 1

    Power Cycle the Printer

    Turn the printer off using the power button. Unplug the power cord from the back of the printer. Wait 60 seconds. Plug the power cord back in and turn the printer on.

  2. 2

    Disconnect Network and USB Cables

    Unplug the ethernet cable or USB cable from the printer. Restart the printer and see if it boots to the ready state without external communication.

  3. 3

    Clear All Print Queues

    Go to settings on every computer that sends jobs to this printer. Open the print queue and cancel all pending or stuck documents.

  4. 4

    Restart the Print Spooler

    On a Windows computer connected to the printer, open services, locate Print Spooler, right click, and select restart. Clear the printer folder inside system32.

  5. 5

    Update the Printer Firmware

    Download the latest firmware for your specific HP printer model from the official HP support website. Install it using a USB cable or via the embedded web server if the printer stays on long enough.

  6. 6

    Switch to a Universal Print Driver

    Uninstall the current printer driver on your computers and install the HP Universal Print Driver in PCL 6 mode to avoid bad command translation.

  7. 7

    Perform a Cold Reset

    Access the pre-boot menu during printer startup and perform a cold reset to clear corrupted NVRAM settings and restore factory defaults.

  8. 8

    Remove Optional Hardware

    If your printer has third party RAM DIMMs, fonts, or EIO network cards installed, power down, remove them, and power back on to test for hardware conflict.

When to contact a professional

Unplug the printer before checking any hardware, and never service internal power supplies yourself. If the error appears instantly upon powering on without network cables attached, and persists after a firmware reinstall and a cold reset, your formatter board is dead and needs hardware replacement. Check your warranty coverage, then contact a professional or HP support.