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Repair a damaged PDF

Load a PDF and rebuild it into a clean copy. Everything stays in your browser, no file is sent to a server.

How Repair PDF works

PDF Repair re-parses a damaged or malformed PDF by loading it through pdf-lib's reader, which tolerates many common structural errors, and then serialises the document back out as a clean, well-formed copy. Bloated cross-reference tables, orphaned objects, minor corruption in the trailer dictionary and other structural irregularities that cause viewers to complain are often resolved by this round-trip. The process runs entirely in your browser, and your file is never sent anywhere.

Be clear about what this tool can and cannot fix. It addresses structural problems: a PDF that is technically parseable but contains internal inconsistencies that confuse viewers or inflate file size. It cannot recover content that is genuinely missing from the file, reconstruct pages that were overwritten, or repair encryption damage. If the file cannot be parsed at all by pdf-lib, the tool will report an error rather than silently produce a corrupt output.

Written by Bastien Sulyan

How to use Repair PDF, step by step

  1. Drop your damaged or problematic PDF onto the upload area.
  2. Click repair to start the re-parse and re-serialisation.
  3. Wait for the process to complete; the tool will show an error if the file cannot be read at all.
  4. Download the repaired PDF and verify it opens correctly in your viewer.

Common use cases

  • A PDF downloaded from an old web server opens with warnings in Acrobat about inconsistent cross-reference data; repair it to remove the warnings.
  • A PDF generated by a legacy application has become bloated over revisions; repair strips orphaned objects and trims the file size.
  • A partially downloaded PDF fails to open; if enough of the file structure is intact, the repair pass may recover readable pages.
  • A PDF passed through multiple conversion tools has accumulated structural noise; re-serialising it produces a cleaner file for archiving.

Frequently asked questions

What kinds of damage can this tool actually fix?

The tool can address structural issues such as inconsistent cross-reference tables, orphaned unreferenced objects, minor header or trailer corruption, and redundant update layers left by incremental saves. It relies on pdf-lib's ability to load the file despite these errors, then re-writes the structure from scratch.

What can it not fix?

It cannot recover content that is genuinely absent from the file, reconstruct a page that was deleted or overwritten, repair corruption inside embedded images or fonts, or help if the file is so damaged that pdf-lib cannot parse it at all. For files where the content is visually intact but the file structure is broken, this tool is a good first attempt.

Will the repaired PDF look identical to the original?

In most cases yes. The re-serialisation preserves all readable content. In rare cases where pdf-lib normalises some internal representation, cosmetic differences may appear, but the semantic content should match the readable state of the original.

Does the tool transmit my file to a repair service?

No. pdf-lib reads and writes the PDF entirely within your browser tab. The bytes stay on your machine from start to finish. There is no server involved and no copy of your document is ever uploaded.

Can the tool reduce file size as part of the repair?

Yes, as a side effect. Re-serialising discards orphaned objects and removes incremental update layers, which can meaningfully shrink a PDF that accumulated bloat through repeated partial saves. For more aggressive compression, follow the repair with the PDF compress tool.

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