How to repair a PDF that will not open
Repair PDF tries to rebuild the internal structure of a damaged document so it opens again and can be saved as a valid PDF.
It is usually needed for files that only half downloaded, attachments that arrived corrupted, or PDFs written by software that gets the cross-reference table wrong, the ones that show errors like "the file is damaged and could not be repaired".
Step by step
- Upload the damaged PDF (or several) with Choose PDF.
- Run the repair.
- Go through the result page by page in the preview.
- Download the repaired PDF or, for several files, the ZIP with all of them.
What can and cannot be recovered
A PDF stores an index that says where each object in the file begins. Many failures come from that index being wrong or missing; it can then be rebuilt by scanning the file, and the whole document opens again.
If data is actually missing, because a download was cut short or a disk lost sectors, pages whose content is not in the file cannot be invented. Not every kind of damage can be fixed, so always check the pages of the result.
Before you repair
If the problem is a password prompt, the file is not damaged: use Unlock PDF if you know the password. If it opens but looks wrong, try another PDF viewer first.
When you can get the original again, download it once more or ask for it to be resent: that is the most reliable repair. Files of up to 50 MB are accepted.
Frequently asked questions
- Can it recover any corrupted PDF?
- No. It works well with broken indexes and structures; content that is not in the file cannot be recovered.
- Does it help with a forgotten password?
- No. Repair does not remove protection, because a password is not file damage.
- Can I repair several files at once?
- Yes. Upload several and you will get the results together in a ZIP.
- Does it change the content?
- The file structure is rewritten; the content of recovered pages is kept. Check the result.
- Why do PDFs get corrupted?
- The usual causes are an interrupted download or copy, an attachment mangled by an email client, or software that saved the file without finishing its internal index.