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How do I fix a corrupted PDF that won't open?

Last updated: 1 November 2026

To fix a PDF that won't open, first download it again or ask the sender for a fresh copy. If that copy is also damaged, run it through Repair PDF, which rebuilds the file's structure and saves a clean copy. PDFs get damaged by interrupted downloads, failing disks, email gateways or buggy software. Often the pages are still inside the file, but the index that tells a reader where to find them is broken.

This guide is for anyone whose PDF reader says a file is damaged, shows blank pages, or refuses to open a file that works in another app. It also covers what repair can and cannot recover, and what to try if the repaired file still has problems.

Open Repair PDF

Step by step

  1. Get a fresh copy first. Download the file again or ask the sender to send it again. If the new copy opens normally, you don't need to repair anything.
  2. Open the repair tool. Go to Repair PDF in your browser. You don't need an account, and the file is processed on your device.
  3. Select the damaged PDF. Click Select PDF file or drop the file onto the page. It's fine if no preview appears, because damaged files often can't be previewed.
  4. Start the repair. Click Repair PDF. If the file is password-protected, enter the password when you are asked for it.
  5. Download the repaired file. Click Download to save the clean copy. Your original file is not changed.
  6. Check every page. Open the repaired file and check that all the pages you need are there. If some are missing or blank, see the section on missing pages below.

What repair can and cannot fix

Repair first runs the file through the QPDF engine, which fixes problems such as wrong stream lengths and broken references. If the file can't be opened at all, the tool scans it object by object, rebuilds the cross-reference table and the page list, and keeps every page it can find.

These kinds of damage can be repaired:

  • Broken or missing cross-reference tables
  • Wrong offsets
  • Files cut off at the end
  • Junk data before or after the PDF data
  • Wrong stream lengths
  • Damaged page lists

What repair cannot do is recreate content that is no longer in the file. If part of the data was never saved or never arrived, there is nothing left to recover.

Signs that a PDF is damaged

  • Your reader says the file is damaged or can't be opened.
  • Pages show up blank.
  • The file opens in one app but not in another.
  • Other PDF tools refuse to accept the file.

Missing or blank pages after repair

When part of a file is lost, for example in a download that stopped halfway, the pages stored in that part are gone. Repair recovers everything that is still in the file, but it can't rebuild pages whose data is missing.

If pages are missing or blank, the data for them was probably lost when the file was damaged, and repair cannot bring it back. Your best option is a complete copy from the source: download the file again on a stable connection, or ask the sender to send it again, then repair the new copy if it still won't open.

If the repaired file still has problems

Some files need a second approach. Try these in order:

  1. Open the original in a different PDF reader. A file that fails in one app sometimes opens in another.
  2. In that reader, save or print the document to a new PDF.
  3. Run the new copy through Repair PDF. Repairing that new copy often helps.
  4. If nothing works, ask the sender for a fresh copy.

Once you have a working file that is too large to email or upload, you can make it smaller with Compress PDF. It resizes and re-compresses large images and never gives you a file that is bigger than the original.

Tools used in this guide

Frequently asked questions

Is my file uploaded when I repair it?

No. The repair runs in your browser on your device, so even confidential documents stay private. You can read more in the privacy policy.

Does repairing change pages that are fine?

No. Intact pages are kept as they are. The repair rebuilds the file structure around them and saves a clean copy. Your original file is not changed.

Can I repair a password-protected PDF?

Yes, if you know the password. You'll be asked for it after you click Repair PDF, and the repaired file keeps its protection.

Why are some pages missing or blank after repair?

When part of a file is lost, the pages stored in that part are gone. Repair recovers everything that is still in the file. To get the missing pages back, you need a complete copy from the source.

No preview appears when I select the file. Is that a problem?

No. Damaged files often can't be previewed. Click Repair PDF anyway, then open the downloaded file to check the result.

Should I try repair before downloading the file again?

Try a fresh download first. If the source is fine, a new copy is the quickest fix. Use repair when the fresh copy is also damaged or when you can't get another copy.

Your files are processed in your browser and are not uploaded. See the privacy policy.