How to Repair a Corrupted or Damaged PDF That Won't Open
Updated July 13, 2026
A PDF that suddenly won’t open — “file is damaged,” a blank viewer, or an outright crash — is usually a structural problem, not a content problem. Repair attempts to rebuild that structure.
Steps
- Open Repair PDF and drop your file.
- Click Repair.
- Download the rebuilt PDF and try opening it.
What actually breaks a PDF
A PDF’s internal structure includes a cross-reference table — essentially an index telling readers where each piece of content lives inside the file. Interrupted downloads, buggy export tools, or a crash mid-save can corrupt that index while leaving most of the actual content intact. When that happens, the reader can’t figure out how to assemble the page, so it fails to open at all, even though the data is mostly still there.
What repair can and can’t do
This tool reads the file with the open-source qpdf engine, which rebuilds the cross-reference structure as it parses the document, and writes out a clean copy — often enough to make a stubborn file open again. What it can’t do is invent data that was truly never written: if pages were cut off mid-save and never fully saved to begin with, no repair tool can bring that content back. It’s always worth trying before giving up on a file, since structural corruption is far more common than actual data loss.
Notes
Everything runs locally via WebAssembly, so even a sensitive document — the kind you’re now worried you might lose — stays on your device throughout. If the file is also password-protected, use Unlock PDF first, then repair the result.