Repair PDF
Recover damaged PDFs that won't open by rebuilding their internal structure.
Damaged PDFs are often important ones: yours is repaired in this browser and never sent to a server.
How do you repair a corrupted PDF that won't open?
Often you can: most of the time the damage is in the internal lookup table that says where each page lives, while the pages themselves are still intact. Docuboxer reads the file in your browser, pulls out every page it can find and writes a new PDF with a rebuilt structure. It handles a broken cross-reference table, a download that was cut off, a missing end of file and junk bytes before the header. If the normal method isn't enough, there is a last resort that draws each page as an image. It is free, needs no signup, and the file never leaves your device, which matters because damaged PDFs are usually contracts, invoices or work with no backup. To be honest about it: it recovers what can be recovered. If a page's content is truly gone, nobody can bring it back, and the report tells you how many pages were saved and how many were not.
How to use Repair PDF
- Drop the damaged PDF into the upload area or click to choose it from your device. Repair starts on its own, and the file is not sent to any server: everything happens in your browser.
- Wait a few seconds and read the report. It names the method that worked (structure rebuild, complete-object salvage or rebuild as images), how many pages came back out of how many the original declared, and any warnings, such as lost pages or leftover data that was stripped.
- Download the repaired PDF. It is saved as "name-repaired.pdf" and your original is never touched, so you can try again as many times as you like.
- Open it in /pdf-reader or your usual viewer and check that the pages you care about are there. If pages are missing or something looks wrong, click "Rebuild as images": it usually recovers more pages, but the text is no longer selectable.
- If the result is larger than you want, run it through /compress. And if the file came from a questionable source, check it with /pdf-scan before opening it in another program.
Common use cases
A PDF that downloaded only partway
The connection dropped mid-download and the file is half the expected size. Your viewer says it is damaged, yet the first pages are complete: they are salvaged and the incomplete part is dropped.
A file that stopped opening after being copied or sent
It went through a faulty USB stick, an email service or a cloud sync that rewrote it badly, and now Acrobat or Preview throws an error. Often only the cross-reference table broke, and rebuilding it is enough.
A PDF saved with extra bytes at the top
A misconfigured server or an email attachment saved from a raw message let text slip in before the start of the file. The leading junk is cut away and the document opens again.
A contract or invoice with no other copy
It is the only copy and you can't request it again. Repairing it in your browser avoids uploading a sensitive document to an unknown service, and even if a page is lost, you know exactly which one.
An old file from a failing drive
A thesis, scans or a project saved years ago on a disk that is starting to fail. Getting most of the pages back in a clean new PDF beats starting over.
Frequently asked questions
Why does my PDF say it is corrupted or can't be opened?
A PDF keeps a table near the end that records at which byte every object starts. If the file was cut off, copied badly or rewritten by a buggy program, that table is wrong and the viewer refuses to open it even though the pages are still there. Repairing means reading the pages another way and writing a fresh table.
Will I get all the content back from a damaged PDF?
Not always. You get back what is still intact in the file. If the download was cut off, the pages at the end are gone and cannot be rebuilt. The report shows how many pages were recovered out of how many the original declared, so you know exactly what is missing.
Do I lose text or formatting when repairing?
With the first two methods, no: pages are copied as they are and text stays selectable. What is not kept is bookmarks, form fields and attachments. With "Rebuild as images" each page is saved as a picture, and then the text can no longer be selected or searched.
Is it safe to repair a PDF with private data on this site?
Yes: repair runs entirely in your browser and the file is not sent to any server. You can verify it by opening your browser's developer tools and watching the network tab while you repair. It is free and needs no account.
What if the PDF is password protected?
An encrypted PDF can't be repaired without leaving it unreadable, so the tool rejects it and links you to /unlock. Remove the protection there with the correct password, then come back and repair it if it still fails.
What if the file isn't a PDF at all?
You get a clear message: no "%PDF-" header was found anywhere, so there is nothing to repair. It usually happens with downloads that were really an error page, or with another file type that was renamed.