HP Error 79: Internal firmware error
Also shows as: 79 Error, 79 Service Error, Turn off then on
The printer has had an internal firmware error. HP notes that under most conditions the printer restarts on its own.
What to try
- Turn the printer off with the power switch, wait at least 30 seconds, then turn it back on and let it initialize.
- If you use a surge protector, remove it and plug the printer directly into the wall outlet.
- If the error comes back, turn the printer off, disconnect network and USB cables, reconnect them, and turn it on again.
- If the printer returns to Ready, check the firmware version and install a newer version if one is available.
- If the error is intermittent, look for a pattern, such as a specific file or connection type. For webpages, try a different browser.
- For PDF files, try the model-specific PCL 6 driver with Print Data Optimization set to Optimize for Raster, or enable Send TrueType as Bitmap, or print with the PCL 5 driver.
When it needs a technician
If the error persists after these steps, HP says to contact an HP-authorized service or support provider or HP customer support.
Which models show 79
HP documents this code for models including HP LaserJet Pro 400 M401, HP LaserJet Pro M701/M706, HP LaserJet P2050 series, HP LaserJet P3010 series.
Varies by model: On some models HP lists "79 Service error" separately and says an incompatible memory DIMM may be installed; HP's advice there is to remove installed DIMMs, retest, and install only a DIMM the printer supports (HP LaserJet Pro 400 M401 control panel messages).
First steps for any printer error
- Write down the exact code before you do anything else — similar-looking codes often mean completely different things.
- Power the printer off, unplug it for a couple of minutes, then power it back on. A surprising number of transient errors clear here.
- Open the covers and check for paper scraps, packaging material, or anything blocking the carriage.
- Check the cartridges or tanks are genuine, correctly seated, and not empty.
- Confirm the printer is plugged directly into a wall outlet, not a power strip or extension lead.
- Check your model’s own manual — codes are model-specific, and the manual is the authority for your machine.
Source: HP Customer Support - 79 Error (or 79 Service Error), Turn off then on. Codes are model-specific, so your own model's manual is the final word. Reviewed October 2026.
Still showing 79?
Tell our printer technician your model and what you've tried. You'll find out whether it's fixable at home or worth repairing at all.
Ask about my printer — $1Eric Paul Amora · Printer & Hardware Repair Technician