Rewrites the PDF through Ghostscript, rebuilding the cross-reference table and object structure. Most 'damaged' files are structurally fine but have a broken index.
In practice: (1) Works when the error is 'cannot open', 'damaged' or 'missing xref'. (2) Pages with corrupt image streams may come through blank. (3) Keep the original until you confirm the repaired copy is complete.
Frequently asked questions
Can you recover a 0-byte file?
No. If the bytes are gone there is nothing to rebuild — restore from backup or the sender.
How do I know repair worked?
Compare the page count and open a few pages; the repaired file should open in any viewer.
Do it in the full tool
Open Repair PDF for all options, or jump straight to another step below.