PDF Shows Wrong Characters or Squares Instead of Text
Text in your PDF appears as squares, question marks, or completely different characters because the fonts are missing or not embedded.
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Missing Fonts in PDF — Wrong Characters, Squares, or Tofu
When you see boxes (□□□), question marks (???), or wrong characters instead of text in a PDF, it almost always means the fonts used in the document are not embedded and are not available on your computer.
How PDF Fonts Work
PDFs can either embed fonts (the font data is stored inside the PDF file) or reference fonts (rely on the viewer to have the font installed). Embedded fonts always display correctly. Referenced fonts display correctly only if the viewer has that exact font.
Diagnosis
Open the PDF in Acrobat Reader → File → Properties → Fonts tab. Any fonts marked as "(Unembedded)" are being substituted. Look for "Embedded Subset" — these are safe.
Fixes
Option 1: Get the Original File
Contact whoever created the PDF and ask them to re-export with fonts embedded. In most apps: File → Export/Save as PDF → check "Embed fonts."
Option 2: Print to PDF
Open the PDF in Adobe Acrobat (even the free Reader sometimes works) → File → Print → choose "Microsoft Print to PDF" or "Save as PDF." This flattens the PDF and may resolve font issues.
Option 3: Google Drive OCR
Upload to Google Drive → Open with Google Docs → the OCR re-creates the text as editable content, losing the original formatting but making it copyable.
Option 4: Install the Missing Font
If you know which font is missing (check File → Properties → Fonts), install that font on your system and reopen the PDF.
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Frequently asked questions
Why does a PDF show squares or unknown symbols instead of text?
This happens when the fonts embedded in the PDF are missing, corrupted, or use a non-standard encoding. The viewer cannot map character codes to glyphs, so it substitutes squares (□) or question marks instead. PDFs that rely on system-installed fonts instead of embedded fonts are the most vulnerable.
Can I fix a PDF showing wrong characters without recreating it?
If the font data is still present but mis-encoded, a PDF repair tool can sometimes correct the encoding. If the font was never embedded, you need to: install the correct font on your system, or "flatten" the PDF in Acrobat (Print Production → Flatten) to rasterise all text as images. The second option removes selectability but guarantees correct display.
How do I prevent font problems when creating PDFs?
Always embed all fonts when exporting to PDF. In Word: Save As → PDF → Options → check "ISO 19005-1 compliant (PDF/A)" — PDF/A requires all fonts to be embedded. In InDesign: check "Embed All Fonts" in the PDF export dialog. In print drivers: use "Embed Fonts" in the PostScript settings.