How AFileFix's Repair PDF works

AFileFix's Repair PDF analyzes a damaged PDF file and reconstructs a valid PDF structure around the recoverable content. The tool re-streams the file, rebuilds damaged xref tables (the internal index of objects), fixes broken trailers (the end-of-file bookkeeping), and recovers as many pages as possible from the original.

Repair runs on our server because the structural analysis needs more compute than a browser provides. Your file uploads over HTTPS, gets processed, and is deleted from our server within minutes after the response is prepared. See our Privacy page for the full retention details.

The result includes a recovered-page count — "N of M pages recovered" — so you know upfront whether the repair was complete or partial.

What gets repaired?

Repair specifically targets PDF structural problems:

xref table corruption — The xref (cross-reference) table is the PDF's internal index of all objects in the file. When it's damaged, viewers can't locate page content, even if the content itself is intact. Repair rebuilds the xref by scanning the file.

Broken trailers — The trailer is the PDF's end-of-file marker that points to the xref and root document object. Corrupted trailers cause some viewers to fail loading entirely. Repair reconstructs a valid trailer.

Invalid object streams — Some PDF files have malformed compressed object streams that confuse readers. Repair extracts what it can from these streams and reformats them.

Misaligned structure — Files that were truncated mid-download or corrupted in transit often have structural offsets that don't match. Repair recalculates these offsets.

What Repair doesn't fix: encrypted/password-protected files (use Unlock PDF — and you'll need the password), scanned PDFs that need OCR (we don't currently offer OCR), and files corrupted beyond structural recovery (truncated mid-transfer, severely damaged binary content).

What does "recovered N of M pages" mean?

After repair, AFileFix reports how many pages from the original document were successfully reconstructed:

Best case: all pages recovered. "10 of 10 pages recovered" — the structural problems were the only issue, and the content was intact. The repaired PDF should open normally in any viewer.

Partial recovery: some pages recovered. "7 of 10 pages recovered" — pages where the underlying content was unrecoverable aren't in the output. They may be missing entirely, or appear as blank pages, depending on the corruption pattern. The repair extracted as much as it could.

Severely damaged: few pages recovered. "1 of 10 pages recovered" — the file was substantially corrupted beyond what structural repair can reach. The output contains what's salvageable, but you may need professional recovery tools or a different copy of the source document.

The recovery count is honest. We don't pad the output with blank pages to make it look more successful than it is.

When is Repair the right tool?

Repair is the right tool when:

• Your PDF won't open in Acrobat ("file is damaged" or similar error)
• The PDF opens but pages are garbled, blank, or out of order
• Another AFileFix tool rejected the file with a "structure" or "format" error
• The PDF was truncated during download (file size is smaller than expected)
• A viewer specifically reports xref or trailer errors

Repair is NOT the right tool when:

• The PDF is password-protected (Unlock PDF — and you need the password)
• The PDF is a scanned image with no extractable text (OCR is a separate process we don't offer yet — it's on our roadmap)
• The file is encrypted with a key you don't have (no tool, free or paid, can decrypt without the key)
• The file is so corrupted that the file format isn't recognizable as a PDF at all

How to test if Repair worked

After downloading the repaired PDF:

1. Open it in your primary PDF viewer. Acrobat is the strictest reader; Chrome and Preview are more forgiving. If Acrobat opens it without errors, the repair is likely complete.
2. Check the page count matches your expectation. Compare against the "N of M pages recovered" message and against your memory of the original document.
3. Check page content randomly. Open a few pages and verify they have the expected content. Blank pages or garbled content indicates partial recovery.
4. Try the failing operation again. If you came to Repair because another tool rejected your PDF, try that tool on the repaired version. Most "structure" errors clear after successful repair.

If the repaired PDF still has issues, the source file may be corrupted beyond structural recovery. In that case, your options are:

• Find a different copy of the source document (often the simplest path)
• Try desktop PDF repair software (some specialized commercial tools can recover from deeper corruption)
• Accept partial recovery and work with what you have

Frequently asked questions