Seeing a flashing light or a sudden error message on your office printer can instantly disrupt your workday. Among the various glitches that laser printers experience, the HP Printer Error 79 is one of the most common—and frustrating.
When this error strikes, your printer will typically freeze, cycle power repeatedly, or refuse to process any incoming print jobs. The control panel usually displays a message like “Error 79: Turn off then on” or “79 Service Error.” Fortunately, this is rarely a sign of permanent hardware failure. In most cases, it is a temporary communication breakdown that you can fix yourself in just a few minutes. This guide will walk you through exactly what this error means, why it happens, and how to resolve it step-by-step.
Quick Answer
The HP Printer Error 79 is a firmware communication error that occurs when a printer receives a corrupted print job, encounters a network glitch, or suffers from outdated firmware. To fix it quickly, clear your computer’s print queue, disconnect the printer from the network, perform a full power cycle, and reconnect it. If the error persists, updating the printer’s firmware will generally permanently resolve the underlying software conflict.
What Does This Mean?
At its core, Error 79 is an internal software conflict. Think of your HP LaserJet printer as a specialized mini-computer. It has its own processor, internal memory (RAM), and an operating system known as firmware.
When you send a document to print, your computer translates that document into a language the printer understands (like PostScript or PCL) and sends it over. If that data stream becomes corrupted, contains unsupported fonts, or includes complex graphics that the printer’s memory cannot parse, the firmware gets confused.
Instead of printing garbage characters or skipping the page, the firmware triggers a safety stop to prevent further damage. This safety stop is what shows up on your screen as a 79 Service Error. It is essentially the printer equivalent of the infamous “Blue Screen of Death” found on Windows computers.
Common Causes
Understanding why your printer threw this code can help you prevent it from happening again. While data corruption is the primary culprit, several specific factors can trigger the event:
- Corrupted Print Jobs: A PDF, webpage, or document that contains broken code or unreadable formatting data.
- Print Queue Bottlenecks: Multiple users sending documents to a shared network printer simultaneously, causing data packets to collide or overlap.
- Outdated Firmware: Older printer firmware that cannot properly interpret modern print drivers or operating system updates (like Windows 11 or macOS Sonoma).
- Network Stability Issues: Sudden drops in Wi-Fi or local network connectivity while a print job is actively transferring.
- Faulty Accessories: Third-party memory modules, font cards, or internal hard drives installed in the printer that have failed or become unseated.
Symptoms vs. Possible Causes
| What You See (Symptom) | What It Usually Means (Possible Cause) |
|---|---|
| Error 79 appears immediately when turning the printer on. | A corrupted print job is stuck in the queue and trying to auto-resume. |
| Error 79 appears only when printing a specific document. | The specific file contains corrupted fonts, complex vector graphics, or formatting errors. |
| The printer continuously reboots itself in a loop. | The firmware is crashing while trying to clear its internal RAM cache. |
| Error 79 occurs randomly across multiple different computers. | The printer firmware is outdated or an internal hardware accessory (like RAM) is failing. |
Step-by-Step Solutions
Before diving into the steps, review the overview table below to gauge the time and effort required for each phase of troubleshooting.
Solution Overview
| Solution Method | Difficulty Level | Estimated Time |
|---|---|---|
| 1. Power Cycle and Queue Clear | Beginner | 5–10 minutes |
| 2. Isolate the Printer Network | Intermediate | 10–15 minutes |
| 3. Update Printer Firmware | Intermediate | 15–20 minutes |
| 4. Reinstall the Print Drivers | Intermediate | 10–15 minutes |
| 5. Remove Hardware Accessories | Advanced | 20–30 minutes |
Step 1: Clear the Print Queue and Power Cycle the Printer
The absolute first thing you must do is remove the toxic data stream that is feeding the error. If you do not clear the print queue on your computer, the moment you turn the printer back on, the computer will attempt to send the bad file again, re-triggering the error.
Why this helps: This flushes out the corrupted data cached in both your computer’s operating system and the printer’s temporary memory.
Procedure:
- Cancel all print jobs on your computer. On Windows, go to Settings > Bluetooth & devices > Printers & scanners, select your HP printer, and open the print queue. Right-click and choose Cancel All Documents. On Mac, open System Settings > Printers & Scanners, open the queue, and click the X next to pending jobs.
- Turn off the printer using the power button.
- Unplug the power cord directly from the back of the printer.
- Unplug the other end from the wall outlet or surge protector.
- Wait at least 60 seconds. This allows the internal capacitors to drain fully, wiping the printer’s volatile memory (RAM) clean.
- Plug the power cord back in. Connect it directly to a wall outlet to ensure it receives stable voltage. Turn the printer back on.
Read Also: How To Fix HP Printer Offline Issue
Step 2: Isolate the Printer from the Network
If the error message reappears immediately upon power-up—even after you cleared your local queue—someone else on your network might be sending a bad print job, or the printer is stuck trying to talk to the network.
Why this helps: Disconnecting the network cables stops all incoming data traffic, allowing you to determine if the issue is internal to the machine or coming from an external device.
Procedure:
- Turn off the printer.
- Disconnect the communication lines. Unplug the Ethernet (LAN) cable from the back of the machine. If the printer uses Wi-Fi, turn off your local Wi-Fi router temporarily, or move the printer far enough away to drop the signal.
- Turn the printer back on while it is completely isolated.
- Check the display. If the printer reaches the “Ready” status without throwing the code, the problem lies with a print job currently sitting on a network computer, server, or print spooler.
How to clear a stubborn network spooler (Windows):
- Press
Windows Key + R, typeservices.msc, and hit Enter. - Scroll down to Print Spooler, right-click it, and select Stop.
- Open File Explorer and navigate to:
C:\Windows\System32\spool\PRINTERS. - Delete every single file inside this folder (do not delete the folder itself).
- Return to the Services window, right-click Print Spooler, and select Start.
- Reconnect your printer’s network cable.
Step 3: Update the HP Printer Firmware
If your printer boots up fine while isolated but crashes the moment it reconnects to the network, its firmware likely has a bug or incompatibility with a recent computer OS update.
Why this helps: Manufacturers frequently release firmware updates to patch known code stability issues, match new security protocols, and fix recurring errors like Error 79.
Procedure:
- Make sure your printer is turned on and connected to your computer via a USB cable (this is safest if the network connection causes crashes).
- Go to the official HP Support & Drivers website on your browser.
- Enter your specific HP printer model number (e.g., LaserJet Pro M402dn).
- Expand the Firmware dropdown category.
- Download the latest firmware update utility tool compatible with your operating system.
- Run the downloaded file. The utility will scan for connected HP printers. Select your printer from the list and click Update or Send Firmware.
- Crucial: Do not turn off the printer, unplug cables, or try to print while the firmware update is in progress. The printer control panel will display a bar showing the progress. Once complete, the machine will restart automatically.
Step 4: Reinstall the Print Drivers
Sometimes, the translator (the driver software installed on your PC or Mac) is corrupted, causing it to generate bad code that triggers the HP Printer Error 79.
Why this helps: Completely removing and replacing old, generic, or broken drivers ensures your computer is sending clean, legible instructions to the printer.
Procedure:
- Disconnect the printer from your computer.
- In Windows, go to Control Panel > Programs and Features, find your HP printer software, and uninstall it.
- Go to Printers & Scanners, select the printer, and click Remove.
- Restart your computer.
- Go back to HP’s driver page and download the HP Full Feature Software and Driver package or use the HP Smart app to perform a fresh installation.
- Reconnect your printer when the installer prompts you to do so.
Step 5: Remove Third-Party Hardware Accessories
If you have tried all the software steps and the printer still boots directly into an Error 79 message even while disconnected from all networks, an internal hardware component may be failing.
Why this helps: Extra internal RAM or fontDIMM modules can degrade over time. Removing them lets the printer run solely on its factory-default motherboard configurations.
Procedure:
- Turn off the printer and pull out the power cord.
- Locate the access panel on the side or rear of the printer (consult your model’s user manual, as locations vary by printer model).
- Open the panel to expose the formatter board.
- If there are any secondary, add-on memory chips (RAM modules) or font cards inserted into the expansion slots, carefully remove them by releasing the retaining clips.
- Close the access panel.
- Plug the printer back into the wall and turn it on. If it works seamlessly, the accessory you removed was defective and needs to be replaced.
Tips to Prevent the Problem
Once you have successfully cleared the error, you want to make sure it doesn’t return. Use these simple preventative maintenance habits to keep your printing environment stable:
- Assign a Static IP Address: For network-connected business printers, login to the printer’s Embedded Web Server (EWS) via your browser and change the network configuration from DHCP to a Static IP. This prevents IP address conflicts among office devices.
- Avoid Mass Web Printing: Avoid printing massively long, unformatted webpages directly from a web browser. Instead, save the page as a clean PDF first, then send it to print.
- Use Genuine Print Drivers: Avoid using generic Microsoft or Apple “Class” print drivers. Always download the model-specific driver directly from HP for accurate document translation.
- Invest in a Quality Surge Protector: Fluctuations in electrical grids can cause micro-interruptions in the printer’s processing board. A dedicated surge protector ensures stable power delivery.
- Perform Quarterly Firmware Reviews: Set a reminder to check for firmware updates every few months to keep your machine in sync with automatic OS patches on your office computers.
Frequently Asked Questions
1. Is HP Printer Error 79 a hardware or software problem?
It is almost always a software or firmware issue caused by data corruption in a print job. However, in rare instances, it can be triggered by a physically damaged formatter board or a corrupted third-party memory stick.
2. Why does my printer keep rebooting itself when Error 79 occurs?
The printer is programmed to auto-restart when its firmware crashes in an attempt to recover. If the corrupted print job remains stuck in the memory or queue, the printer will load it immediately upon rebooting, causing it to crash and restart indefinitely.
3. Will resetting my HP printer to factory defaults fix Error 79?
Yes, a factory reset can help clear persistent settings errors or corrupted configurations. However, you should try clearing the print queue and updating the firmware first, as a factory reset will erase all your custom network setups and saved preferences.
4. Can a specific file format cause this error?
Yes. Complex PDF files with multiple overlapping vector graphics layers, non-standard embedded fonts, or corrupted metadata are the most frequent triggers for this specific error code.
5. What is the difference between Error 79 and Error 49?
Both errors point to a communication failure, but Error 49 usually deals with communication protocols or firmware commands that the printer cannot process. Error 79 typically relates directly to an invalid payload or corrupted data within the print engine stream itself.
6. Can I still use my printer if I skip the firmware update?
If the error was caused by a one-off corrupted file, your printer will work fine after clearing the queue without a firmware update. However, if the error was triggered by a systemic incompatibility with your computer’s operating system, the error will likely keep recurring until the firmware is updated.
7. Does this error mean I need to buy a new formatter board?
Not necessarily. Replacing the formatter board is a last resort. Always attempt to clear the print queues, isolate the network, and update firmware before concluding that the physical hardware is broken.
8. Why did this error start happening after a Windows update?
Windows updates frequently change print management configurations, spooler behaviors, or security authorizations. If your printer’s firmware is old, it might not know how to interact with the updated Windows security architecture, triggering a system crash.
Final Thoughts
Dealing with an HP Printer Error 79 can be deeply inconvenient, but it is rarely a terminal diagnosis for your office equipment. By thoroughly clearing out corrupted data queues, isolating the machine from conflicting network traffic, and ensuring your device’s firmware is up to date, you can typically get your printer back online without paying for a professional repair technician.
