You open a PDF and get “file is damaged”, nothing happens, or the pages are blank. Here are the common causes, what to check first, and how to repair the file in your browser.
In short
- Download it again or ask for a new copy first. If an original exists, that works best.
- Try another viewer, such as your browser or Acrobat Reader.
- Still broken? Use repair PDF to rebuild the file structure. It runs in your browser; the file is not uploaded.
What a PDF is made of, and why it breaks
The PDF 1.7 specification (ISO 32000-1) describes four parts in a basic PDF file:
| Part | What it does |
|---|---|
| Header | The first line, %PDF- followed by the version |
| Body | All the objects that make up the document |
| Cross-reference table | Where each object sits in the file, so a reader can jump to any page without reading everything |
| Trailer | Points to the cross-reference table; the last line must be %%EOF |
The specification says readers should read a PDF from its end. So if the end is cut off, for example by an incomplete download, the part that leads to the cross-reference table goes with it (our conclusion from the structure the specification describes). It also says that when the cross-reference table is damaged or missing, a reader may try to rebuild it by scanning all the objects in the file.
Check whether it’s really damaged
- Incomplete download: Google suggests checking your connection, resuming the download, or cancelling and using right-click › Save link as. Adobe suggests downloading again or asking for a resend if the file came from the web or e-mail.
- The attachment is winmail.dat: Microsoft explains this appears when the recipient’s mail system can’t process Outlook’s TNEF format; the original attachment may be inside, but the file has no useful information when opened. Ask the sender to resend without that format.
- Password-protected: Adobe treats “can’t open a password-protected PDF” as a separate problem from damage. If you know the password, use unlock PDF.
- Renamed extension: Apple warns not to change a file’s extension when renaming it, or you may no longer be able to open it. Renaming a photo or Word file to .pdf doesn’t make it a PDF.
- The viewer: Adobe suggests updating Acrobat Reader, making it the default PDF app, or downloading a PDF that opens in the browser and opening it in Acrobat Reader.
Adobe says that if a PDF is truly damaged, you should recreate it from the original source file. If you have the source, that’s always best.
Repairing step by step
- Open repair PDF and choose the file (the preview may not appear because the file is damaged; that’s fine).
- Press repair. The tool tries one method at a time:
- Method 1: qpdf rebuilds the damaged cross-reference table. The qpdf manual says it attempts this reconstruction when it hits errors reading a file and is usually successful, but uses heuristics that don’t work on all files.
- Method 2: read whatever can still be read and build a new file.
- Method 3: draw every page that still displays as a picture and combine them into a new PDF. Text in the new file can’t be selected.
- The page tells you which method worked and how many pages it got. Download it and check that every page is there.
The qpdf manual itself warns that recovery won’t always give the desired result even when it gets through the file, and a partly downloaded file can only be recovered as far as it goes.
After repairing
- If the file got bigger, especially from method 3, shrink it with compress PDF.
- For important documents such as contracts or receipts, ask the sender for the original again; a recovered file can be missing parts without you noticing.
Note
This article is based on help pages from Adobe, Google, Microsoft and Apple, Adobe’s edition of the PDF 32000-1:2008 specification (copy in the Internet Archive) and the qpdf manual, read on 30 September 2026.
