A PDF that looks correct in one viewer but displays garbled text, missing characters, or rendering errors in another typically has font embedding issues or structural problems. Here are the common causes and free fixes.
Garbled or replaced text (characters appear as symbols or squares): missing embedded font. Different appearance in Chrome vs Adobe Reader: font substitution differences. Blank pages in some viewers: unsupported PDF feature or corrupted object stream. Overlapping text or shifted layout: incorrect page geometry or coordinate system errors.
Go to pdfeditor.onl/repair-pdf. Upload the problematic PDF. The tool re-serializes the PDF structure — correcting object stream issues, repairing cross-reference tables, and normalizing the document structure that can cause viewer-specific rendering differences.
Use the Flatten option in pdfeditor.onl/repair-pdf. Flattening converts every page to a high-resolution raster image embedded in the PDF. This bypasses all font and layout issues because the page becomes an image — rendering identically in every viewer.
Tip: Flatten is the nuclear option — it resolves almost all rendering issues but makes the text no longer selectable (since it becomes an image). Run OCR afterward if searchable text is needed.
If you have the original Word or InDesign file, re-export to PDF with font embedding enabled (the default in most modern applications). In Word: File → Save As → PDF Options → ISO 19005-1 compliant (PDF/A) embeds all fonts.
Scanned PDFs should not have text at all — they are images. If a scanned PDF shows garbled text, an OCR layer was incorrectly applied. Use pdfeditor.onl/ocr-pdf to re-apply OCR, overwriting the faulty text layer.
Chrome and Adobe Reader use different font rendering and substitution engines. When a font is not embedded in the PDF, each viewer substitutes a different replacement font — creating different (sometimes broken) appearances. Embedding fonts or flattening solves this.
Blank pages can be caused by transparent content layers, missing resources, or rendering failures. Try the Repair tool first. If pages remain blank, the PDF may have invisible white content on white background — try flattening which forces all layers to render.