How to use Repair PDF
- 1
Choose the PDF that will not open properly.
- 2
Press Repair PDF. The file is scanned and its structure rebuilt.
- 3
Download the repaired copy and check it in your usual viewer.
What usually goes wrong
Most “corrupt” PDFs are not destroyed, just inconsistent. A download that stopped early, an email gateway that changed line endings, or a program that crashed while saving can leave the file’s cross-reference table pointing at the wrong byte offsets. Viewers that trust that table fail to find the pages.
How the repair works
FileSwiftly uses QPDF, a well-known open-source PDF library compiled to run in your browser. It reads the file object by object, ignores the broken index, rebuilds a correct one and writes out a clean PDF. If that fails, a second pass renders whatever pages can be read and rebuilds the document from those page images, so you at least recover readable pages.
What cannot be recovered
Content that is truly missing — the last pages of a truncated download, for example — cannot be invented. When the repair succeeds only partially, the result screen tells you how many pages were recovered.
Honest expectations
Repair is best-effort. If both passes fail, the file is probably too badly damaged, or it is not a PDF at all (some “PDFs” are renamed HTML error pages). Try downloading the original again.
Repair PDF: frequently asked questions
Will repair change how my PDF looks?
The first pass keeps all content as it was. The fallback pass converts pages to images, which makes text unselectable; the result screen tells you if that happened.
Can it repair password-protected PDFs?
If the file needs a password to open, unlock it first with Unlock PDF.
My PDF opens fine — should I run repair anyway?
Repair can also help when a PDF opens but fails to print or upload to a portal, because it writes out a strictly standard file.
Is my damaged file uploaded for analysis?
No. Everything happens in your browser.