HP Printer Error Code 21: How to Fix It

Easy 15-45 minutes Medium Severity Verified June 2026
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Error Code
21
Brand
HP
Product Type
printer
Severity
Medium
DIY Difficulty
Easy
Estimated Fix Time
15-45 minutes
HP Printer Error Code 21 — often displayed as '21 PAGE TOO COMPLEX' — means the printer's memory cannot process the data required to print the page. This typically happens when a document contains too many complex graphics, fonts, or high-resolution images for the printer's built-in memory to handle. The good news is that this error is almost always fixable through software settings, driver updates, or a small hardware upgrade, without needing a service technician.
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Tools You'll Need

How to Fix Error Code 21

  1. Cancel the Print Job and Restart the Printer

    Always unplug the printer from the wall before touching any internal components. Restarting alone (without unplugging) may not fully clear memory — a full power cycle is recommended.

  2. Reduce the Complexity of the Document

  3. Change Print Quality Settings to Lower Resolution

  4. Enable 'Print Page as Raster' or 'Print as Image' in Printer Settings

  5. Update or Reinstall the HP Printer Driver

    Ensure you download the driver directly from HP's official website (hp.com/support) only. Avoid third-party driver sites, which may install malware.

  6. Increase Printer Memory (RAM Upgrade)

    Unplug the printer from the wall before opening any access panels or touching internal components. Ground yourself by touching a metal surface to avoid static discharge that could damage memory modules.

  7. Split the Document into Smaller Sections

  8. Reset the Printer to Factory Defaults

    A factory reset will erase all custom printer settings, saved networks (for wireless models), and stored jobs. Note down any custom configurations before performing a reset.

Parts You May Need

Printer memory DIMM module
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Printer memory DIMM module
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Printer memory DIMM module
Check Price on Amazon
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When to Call a Professional

If you have tried all steps above — including reducing document complexity, updating drivers, enabling raster mode, and upgrading printer memory — and Error 21 still appears consistently, the printer's formatter board or memory controller may be failing. At this point, contact an HP-authorized service technician or HP support directly at hp.com/support. Additionally, if your printer is still under warranty, do not attempt a memory upgrade yourself, as it may void the warranty — contact HP support instead.

Frequently Asked Questions

What does HP Printer Error Code 21 mean?
HP Printer Error Code 21 means the page you are trying to print is too complex for the printer's memory to process. It typically appears as '21 PAGE TOO COMPLEX' on the printer's display. It is caused by documents with large images, many fonts, or high-resolution graphics that exceed the printer's available RAM.
Can I fix HP Error Code 21 without buying new parts?
Yes, in most cases. You can fix Error 21 by lowering print resolution in your driver settings, enabling 'Print as Image' mode, simplifying the document, or updating your HP printer driver — all of which are free. A hardware memory upgrade is only needed if the error happens repeatedly with normal documents.
Will adding more RAM to my HP printer fix Error Code 21?
Yes, adding a compatible memory DIMM module to your HP printer is one of the most reliable permanent fixes for Error 21. More RAM allows the printer to handle complex pages with heavy graphics or many fonts. Check your specific HP printer model's manual or HP's website to find out if your model supports memory expansion and what memory type it requires.
Why does HP Error 21 only happen with certain documents?
Error 21 is triggered by page complexity, not all documents equally. Files with embedded high-resolution photos, complex vector graphics, many different fonts, or large PDFs require much more printer memory than simple text documents. If only specific files trigger the error, simplifying those files (lowering image resolution or reducing graphics) will usually solve the problem.
Does HP Error Code 21 mean my printer is broken?
No, Error Code 21 does not mean your printer is broken or damaged. It is a memory limitation error, not a hardware failure. The printer is working correctly — it is simply telling you that the document you sent is too complex for its current memory to process. Following the steps in this guide will resolve the issue in most cases without any repairs needed.

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