Printer printing gibberish: how to stop random characters, symbols and code

A printer printing gibberish is almost never a broken printer. It is a printer that has received data it cannot make sense of, so it prints the raw data instead: random letters, rows of symbols, a single odd character at the top of many pages, or whole sheets of what looks like programming code. This guide helps you read what the gibberish is telling you, then works from the free fixes to driver changes.

If pages come out completely empty instead, see printer printing blank pages. For every other symptom, start from the printer troubleshooting guide.

Read the gibberish first

The kind of nonsense on the page narrows the cause quickly.

What prints	What it usually means	Start with
Pages beginning with %!PS or %!PS-Adobe	PostScript sent to a printer not using PostScript	Driver language
Lines with @PJL, ESC or short codes like E or &l	PCL or job commands sent to a printer that does not read them	Driver language
Random characters, then a page stops mid-way	Corrupted or interrupted job	Queue and restart
Gibberish that starts when the printer is switched on	Half-sent job still arriving	Queue and restart
One document with boxes, Greek letters or wrong symbols	Font substitution	Fonts
Garbage from every program, sometimes fine	Cable, port or hub	Connection

Fix 1: Clear the queue and restart everything

A job that was cancelled while it was being sent, or a computer that went to sleep mid-print, can leave a damaged job in the queue. The printer receives the second half of it, without the start that tells it what language it is reading, and prints it as text.

Windows 11: open Settings > Bluetooth & devices > Printers & scanners, select the printer and choose Open print queue. Cancel every job. If jobs refuse to disappear, follow the steps in print spooler error fix to stop the Print Spooler service and empty the spool folder.

macOS: open System Settings > Printers & Scanners, select the printer, click Printer Queue and delete all jobs.

Then switch the printer off, wait a minute and switch it on again. A printer holds partly received data in memory until it is reset.

Fix 2: Print two test pages

1. Print a configuration or printer status page from the printer’s own menu. This comes from the printer’s memory and never touches the computer.
2. Print a test page from the computer. In Windows 11, open the printer in Printers & scanners and choose Print test page.

If the printer’s own page is also gibberish, the printer’s electronics or firmware are at fault; skip to the last section. If the printer’s page is clean but the computer’s test page is not, the problem is the driver, the port or the cable. If both are fine but one program prints rubbish, the problem is the file or the application.

Fix 3: Check the cable and the port

For USB printers, try a different short cable plugged directly into the computer, not into a monitor, dock or unpowered hub. A cable that is only partly faulty can let some data through and corrupt the rest.

For network printers on Windows, open the printer’s Printer properties and the Ports tab. Make sure the selected port points to this printer’s current IP address. A port that points to a different printer on the network, such as an older model that uses another printer language, will produce gibberish on that other printer.

Fix 4: Match the printer language (PCL or PostScript)

Laser printers and many office printers understand one or more page description languages, mainly PCL and PostScript. The driver translates your document into one of them. If the driver writes PostScript and the printer expects PCL, or the other way round, the printer prints the commands as plain text.

• Many manufacturers offer more than one driver for the same model, for example a PCL driver and a PostScript driver. Check your printer’s specifications on the manufacturer’s support site to see which languages it supports, and install a driver for one of them.
• Some printers have a printer language or personality setting in their menu. Set it to automatic if that option exists.
• Make sure the driver is for your exact model. A driver for a similar model name can use a different language.

To replace the driver cleanly on Windows 11, remove the printer, then open Print server properties (from the related settings at the bottom of Printers & scanners), go to the Drivers tab, select the old driver and choose Remove > Remove driver and driver package. Add the printer again afterwards. If Windows reports the driver as missing after this, see printer driver is unavailable.

On a Mac, remove the printer in Printers & Scanners and add it again. In the add printer window, the Use menu lets you pick the specific driver, a generic PostScript or PCL option, or AirPrint where supported.

Fix 5: Test with a generic driver

A generic driver tells you whether the manufacturer’s driver is the problem.

• Windows 11: many network printers can be added with the Microsoft IPP Class Driver. For a quick check of whether any data gets through cleanly, the Generic / Text Only driver prints plain text from Notepad.
• macOS: AirPrint, or Generic PostScript Printer for printers that support PostScript. If a third-party add-on in the print dialog is suspected, Apple suggests selecting Use Generic Printer Features under Options & Supplies.

If the generic driver prints correctly, keep it or reinstall the manufacturer’s driver from scratch. Mac users who still have problems can work through printer not working on Mac.

Fix 6: Fonts and individual files

When only one document prints wrong characters, the printer is fine.

• In a PDF reader, look for Print as image in the advanced print options. If a PDF fails completely rather than printing symbols, see printer won’t print PDF.
• Save the document as a PDF with fonts embedded and print that.
• On some PCL drivers, an advanced option controls how TrueType fonts are sent. Choosing to download them as soft fonts instead of substituting printer fonts can fix wrong symbols.

Inkjet and laser printers

Gibberish is most common on laser and office printers because they rely on PCL or PostScript. Home inkjets usually use their own driver-specific language, so on an inkjet the fix is nearly always clearing the queue, checking the cable and reinstalling the correct driver.

When it is not worth repairing

If the printer’s own configuration page prints as gibberish after a restart, or the printer prints rubbish before any computer is connected, the formatter board or firmware has failed. Check the manufacturer’s support site for a firmware recovery procedure for your model first. If none exists, a replacement board on an older or inexpensive printer usually costs too much compared with a new printer, so compare prices before you decide.