Repair PDF
Rebuilds a damaged PDF's internal structure. Fixes a good share of files that fail with 'damaged or corrupted' errors, especially ones broken by an interrupted download or transfer.
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- ProcessingOn your device
- Uploaded to a serverNothing
- InternetNot needed
Don't take our word for it. Turn off your Wi‑Fi, then use this tool. It will work exactly the same, which is only possible because your file never goes anywhere.
Worth knowing
Repair can only rebuild what's still in the file. If the actual page data was lost, no tool can bring it back — and this one will say so rather than hand you an empty document.
What a broken PDF usually turns out to be
A PDF that will not open is rarely destroyed. Most of the time the file is intact but its index is wrong, and a reader that insists on a valid index gives up before trying anything else.
The cross-reference table
Every PDF ends with a table listing where each object lives in the file. Software that writes a PDF badly, or an edit that does not update the table, leaves the reader with a map that no longer matches the territory. Repair rebuilds that map by scanning the file for what is actually there.
Before you try repairing
- Check the file size. A file much smaller than expected, or exactly 0 KB, is a failed download rather than a damaged document — fetch it again.
- Check the real format. Files arrive named .pdf that are actually Word documents or images; renaming does not convert them.
- Try a different reader. Some are far stricter than others, and a file that fails in one often opens in another.
- Check whether it is simply locked. A password prompt is not damage.
What repair cannot do
If the file is genuinely truncated, the missing bytes are missing. Repair can often recover the pages that did arrive, which is usually better than nothing, but it cannot invent the rest. A file that stops halfway through needs downloading again from the source.
More on this: the full repair checklist.
Questions people ask
What kinds of damage can this fix?
Broken cross-reference tables, bad page trees and truncated structure — the most common causes of 'cannot open' errors. Genuinely missing content can't be recovered.
Will repairing change my document?
The structure is rebuilt; the content is not rewritten. Pages that were readable come out as they were.
Can it recover a partly downloaded file?
Often it recovers the pages that completed. Anything that never arrived cannot be reconstructed — download the file again if you can.
The file still will not open. What now?
Check that it is really a PDF: open it in a text editor and look at the first line, which should begin with %PDF. If it does not, the file is something else wearing a .pdf name.
How to use it
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Why won't my PDF open? A repair checklist.
A PDF that refuses to open is usually truncated, mislabelled or locked rather than genuinely corrupt. Work through these checks in order before you give up on the file.