Why does a PDF print strange characters instead of readable text?
Quick answer
First compare the PDF on screen and try printing it from a different PDF viewer or application, checking that the intended printer is selected. If the problem happens only in one app, focus your next checks there. If your PDF software offers “Print As Image,” you can try it as a workaround; it may print more slowly. These checks narrow possibilities, but do not by themselves prove a font problem or file corruption.
The question, the details, the next step.
Why does a PDF print strange characters instead of readable text? It looks fine on my screen, but the paper has random symbols.
Treat it as a troubleshooting question, not proof that the PDF is damaged. Start with two comparisons: open the same PDF in another viewer, and try printing a different document from the original app. Also confirm that the intended printer is selected. HP lists an incorrect printer driver, the application, or the operating system among possible factors for garbled or incomplete output on specified printer models; that is guidance for those models, not a diagnosis for every printer. [S1]
If you can, keep the original PDF unchanged while testing. Write down which app and printer you used for each attempt.
The PDF looks normal in my usual viewer. Should I assume it has missing fonts?
No. A normal on-screen preview does not establish what caused the printed characters. The supplied printer guidance does not specifically establish missing fonts as the explanation, so treat that as an unconfirmed possibility rather than a finding. [S1]
Compare the PDF in a second viewer, if available. If it looks different there, note that difference. If both previews look readable but the print is garbled, record that too; it helps separate a display difference from a print-path problem without claiming which component is at fault.
How do I tell whether it is this PDF or the printer or app?
Change one thing at a time and note the result. Try the same PDF from a different application; then try a different, ordinary document from the original application. HP’s Windows guidance recommends comparing output from different software. If printing works elsewhere, the original program is a possible factor, but that comparison alone does not prove the cause. The guidance is specific to HP printers and Windows. [S2]
Example notes:
- Same PDF, Viewer A, Printer 1: symbols.
- Same PDF, Viewer B, Printer 1: readable.
- Different document, Viewer A, Printer 1: readable.
This pattern points your next investigation toward Viewer A, but it is not a definitive diagnosis.
Could the PDF itself be corrupt? What about the print-as-image option?
You can test the PDF with another viewer or compare it with a fresh copy from the original sender or source, if one is available. A different result is useful evidence to record, but these checks do not prove that the file was corrupt. The supplied HP guidance does not establish PDF corruption as a cause. [S1] [S2]
If your PDF application offers “Print As Image,” it is reasonable to try it as a workaround. HP describes that option for some PDF printing problems and notes that output may be slower; availability and behavior can vary, so this is not a universal fix. [S1] Print one test copy and compare it with the ordinary print before relying on it.
What should I send to support if none of that helps?
Send a concise troubleshooting record rather than guessing at a cause. Include the PDF’s filename or a safe placeholder, whether it looks readable in each viewer, which app and printer were selected, and what happened in each test. Add whether “Print As Image” was available and what changed when you tried it. Avoid sending sensitive document contents unless the support channel and your organization’s process allow it.
A useful report could say: “The PDF looks readable in Viewer A and Viewer B. It prints as symbols from Viewer A and as readable text from Viewer B to [printer model]. A different document prints normally from Viewer A. ‘Print As Image’ [was available / was not available]; the test [result].” This describes observations without claiming a diagnosis.
A practical checklist
Confirm the intended printer is selected before printing.
Check whether the PDF looks readable in a second viewer.
Print the same PDF from another application and note the result.
Try a different document from the original application as a comparison.
If offered, test “Print As Image” and note any change or slower output.
Record the app, printer, and results of each test for support.
A few more useful answers
Does garbled printing prove that the PDF is corrupt?
No. The supplied guidance does not establish PDF corruption as the cause. Compare the file in another viewer or with a fresh copy, and report what changes without treating that as proof.
Is “Print As Image” a guaranteed fix?
No. HP recommends it for some PDF printing problems and notes that it may be slower, but the option is context-specific and may not be available in every PDF application. [S1]
What if the PDF prints correctly from another app?
Record that result and focus your next checks on the original application. HP’s Windows guidance treats successful printing elsewhere as a clue that the original program may be involved, not a definitive diagnosis. [S2]
Sources
References used for this guide.
- [S1] HP LaserJet MFP M437–M443 and related models: Printing problems support.hp.com · Checked
- [S2] HP Printers - Unexpected Text Prints (Windows) support.hp.com · Checked