How to Fix Your Printer When It Starts Printing Gibberish

Last updated: September 24, 2026.

Quick answer: When a printer spits out pages of random symbols, code or garbled text, the computer is sending data the printer can't interpret. Usually it's the wrong or corrupted driver, a stuck print job, or a PDF the printer can't read. Cancel every job in the queue, turn the printer off and on, restart the print spooler, then reinstall the correct driver for your exact model. That fixes the large majority of cases.

Why Is My Printer Printing Gibberish or Random Characters?

Printers understand specific "languages", such as PCL, PostScript or a manufacturer's own format. The gibberish is the raw data being printed as plain text because the printer didn't recognize it. The most common reasons:

• Wrong driver. For example, a PostScript driver talking to a PCL-only printer, a driver for a similar model, or a generic Windows driver.
• A corrupted or stuck job in the print queue that keeps resending half-finished data.
• A damaged or unusual file, most often a PDF with embedded fonts or layers the printer can't process.
• Connection problems, such as a failing USB cable, an unpowered hub, or a Wi-Fi dropout mid-job.
• Printer memory full on large or graphics-heavy documents.
• Malware or a misconfigured app sending junk data. This is rare, but it happens.

How Do I Fix a Printer That Prints Gibberish?

1. Stop the flood. Press Cancel on the printer, then open the print queue on your computer and cancel every job.
2. Power cycle the printer. Turn it off, unplug it for 60 seconds, and turn it back on. This clears its memory.
3. Restart the print spooler. On Windows, open Services, find Print Spooler, and choose Restart. Step-by-step instructions for Windows and Mac are in how to restart a stuck print spooler.
4. Print a simple test, like a one-line text document. If that prints correctly, the problem is the original file, not the printer.
5. Remove and reinstall the driver. Delete the printer from your device list, download the full driver for your exact model from the manufacturer's support site, and add the printer again. Avoid "similar model" drivers.
6. Check the connection. Swap the USB cable, plug directly into the computer, or move the printer closer to the router.
7. Try a different driver language if your printer offers both PCL and PostScript (PS) drivers. Switch to the other one.

If Windows reports the driver is missing entirely, see "printer driver is unavailable".

Why Does My Printer Print Gibberish From PDFs Only?

PDFs can contain fonts, transparency and layers that some printers, especially older lasers, can't process. In Adobe Acrobat or Reader, open the print dialog, click Advanced, and tick Print as Image. The computer then sends a simple picture of each page instead of complex PDF data. Printing from a different PDF viewer, or re-saving the file, also works.

Why Is My Printer Printing Code After a Windows Update?

Windows updates sometimes replace a manufacturer's driver with a generic Microsoft one, or change the printer's port. Reinstall the manufacturer's full driver package, then check under Printer Properties → Ports that the printer is on the right port (a USB port, or its IP address for network printers).

What About Thermal and Label Printers Printing Random Characters?

Receipt and label printers (Zebra, Rollo, Dymo and similar) speak their own languages, such as ZPL, EPL or ESC/POS. Printing random characters usually means the app is sending the wrong language, or the printer's emulation mode was changed. Set the correct language in the printer utility, recalibrate the label size, and use the manufacturer's driver. Thermal paper basics are covered in our thermal printer paper guide.

Frequently Asked Questions

More fixes for common printer problems are in the printer troubleshooting center.