PDF file repair guides

A practical guide to fixing PDFs that came out corrupted from a merge operation. Covers re-merging with reliable tools, repairing broken outputs, and avoiding the cause.

How to recover bookmarks, annotations, form data, or signatures lost after PDF repair — and how to avoid losing them next time.

A practical guide to compressing oversized PDF files. Covers Ghostscript compression presets, image downsampling, font subsetting, and when compression hurts quality.

When a PDF displays text as boxes, question marks, or the wrong font, the cause is usually unembedded fonts. Here's how to diagnose and fix it.

PDF forms come in two technologies — AcroForm and XFA — and most fill-or-save problems trace back to which one you have. How to identify and fix each.

Fixing PDFs that arrived broken via email. Covers the fastest fix, structural repair when re-requesting isn't an option, and why email transit damages PDFs.

Fixes for PDF email attachments that won't open. Covers transport corruption, Outlook temp folder issues, and when to ask the sender to resend.

When images in a PDF render as blank rectangles or fail to display, the problem is usually in the image stream or your reader. Diagnosis and fixes.

A practical guide to fixing PDFs that came out broken when exported from Microsoft Word. Covers source-document issues, export tool problems, and rebuild paths.

Fixes for PDFs that open but display blank or black pages. Covers rendering issues, missing fonts, XFA forms, and content stream problems.

What actually works when you've lost a PDF password, what doesn't, and how to tell the difference. Covers encryption levels, realistic recovery options, and when to stop.

Fixing corrupted output from PDF split or page-extraction operations. Covers re-splitting with reliable tools, repairing broken outputs, and prevention.

When a PDF rejects a password you know is correct, the cause is usually copy-paste, encoding, or encryption-dictionary related. How to diagnose each.

Mobile PDF readers are stricter than desktop versions and reject files desktop tolerates. Here's how to identify the cause and produce a mobile-compatible file.

When a PDF reports it's locked by another process, the file isn't corrupted — something on your system holds an exclusive handle. How to find what, and release it.

Practical fixes for PDFs that won't open, ranked from zero-effort diagnostic to command-line repair. Covers the common causes and when to stop trying.

PDFs that open fine but fail when printing usually have transparency, font, or driver problems. Here are the fixes that work, in order.

A scanned PDF without searchable text isn't corrupted — it's an image-only PDF that needs OCR to add a text layer. Here are the tools and recipes that work.

Fixes for Acrobat's 'file is damaged and could not be repaired' error. Covers the common causes, ranked strategies, and when Acrobat's own installation is the problem.

What Acrobat's signature-invalid error means, why it can appear on documents nobody modified, and how to investigate, fix, and avoid it for legal and audit workflows.

What the PDF-XChange Editor error "PDF Structure 40: Invalid reference table (xref)" means, why it appears, and how to repair the underlying file in a few minutes.

What Adobe Acrobat's security warnings mean, when they signal a real risk, and how to allow trusted PDFs to run scripts without disabling security across the board.

What "cross-reference table not found" means in a PDF, why readers report it, and how to rebuild the xref. Covers qpdf, Acrobat, and Ghostscript paths.

What qpdf's "expected N 0 obj" and "expected endobj" warnings mean, why they appear together with file is damaged, and how to recover the PDF in one command.

When macOS Preview can't open a PDF, the cause might be the file, the application, or Preview's cache. How to identify which and fix it.

Adobe's catch-all 'not supported or damaged' error covers four distinct problems. How to identify which one you have, in order, before reaching for a repair tool.

Adobe's numbered PDF error codes — 14, 109, 110, 111, 135 — what each one means, what causes them, and the universal Chrome 'wash' that resolves most of them.

When Acrobat reports a PDF has no pages, the file's page data is genuinely missing — not just unreachable. Why this happens and what your options actually are.