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Repair PDF
Repair PDF reloads a damaged file while ignoring encryption flags and re-saves it with object-stream optimisation, which rewrites the cross-reference table that most 'this file is corrupted' errors come from. It is a structural repair, not a content recovery service.
How to use Repair PDF
- Upload the PDF that fails to open or renders partially.
- Run the repair pass; the tool reloads the document and rebuilds its internal indexes.
- Download the repaired copy and open it in your usual reader to confirm the result.
Where Repair PDF is useful
- Recovering a download that was interrupted halfway and now errors on open.
- Fixing a file whose page tree is intact but whose cross-reference table is stale.
- Cleaning up documents produced by older or non-standard PDF writers.
Formats, algorithms and limits
PDF files end with a cross-reference table that maps every object to a byte offset. When that table is damaged — the classic cause of corruption warnings — the document contents are often still intact. Repair rebuilds the table, discards unusable metadata and writes the file back with compressed object streams.
Troubleshooting and honest limits
- If the repair fails, the object data itself is probably damaged beyond structural repair; try another copy of the file first.
- Repair cannot recreate pages that were never saved; it only rebuilds indexes around existing content.
- Some viewers cache a damaged file aggressively — close and reopen the reader after repairing.
Frequently asked questions
What kind of corruption can this tool actually fix?
Damaged or missing cross-reference tables, stale byte offsets, and files that throw errors because of unusual encryption flags. It does not reconstruct pages whose data was never written to disk.
Does repair remove the password from my file?
It reloads the document while ignoring encryption restrictions so the structure can be rebuilt. Use it on files you own or are authorised to access — the proper route for a locked document is Unlock PDF.
Will repairing change how the document looks?
In a successful repair the visible pages are the same content, re-indexed. Some non-essential metadata may be dropped because it could not be parsed.
Is my file uploaded anywhere during repair?
No. The document is read into the browser tab, rebuilt in memory with pdf-lib, and written straight back to a download.
Related tools
Page written and reviewed by the FreeConvertio engineering team on 2026-10-14. Repair PDF runs entirely in your browser — no uploads, no account and no daily limits.