How repair works
- Upload a PDF that fails to open, shows blank pages, or throws an error in another reader.
- Method 1 — structure rebuild: the tool parses whatever is still valid in the PDF object tree and writes a fresh xref (cross-reference) table so viewers can navigate the file.
- Method 2 — page-level recovery: if the structure is too badly damaged, pages are rendered to images and stitched into a clean new PDF. Text becomes non-selectable, but at least the content is saved.
When repair helps
- Download was interrupted and the last few bytes are missing — Method 1 usually recovers cleanly.
- Email attachment got truncated — Method 2 often salvages the visible pages.
- An old PDF from a discontinued program refuses to open in modern Acrobat / Preview.
- Phone storage filled up mid-save and the file ended up malformed.
Frequently asked
How bad can the damage be and still be repairable?
If PDF.js can read even one page, Method 2 will produce something useful. If the file is truncated mid-stream, the final few pages may be lost — but earlier pages usually survive.
Will repair recover deleted content?
No. Repair only reconstructs what is still in the file. Content deleted in another editor is not recoverable.
Is Method 2 output searchable?
No — Method 2 rasterises pages to images. Run OCR afterwards to restore searchability.
Will the file size change?
Method 1 output is usually similar in size. Method 2 output depends on page count and image quality — it is typically larger because pages become JPEGs.
Privacy: All repair logic (parsing, rendering, rebuilding) runs in your browser with PDF.js and pdf-lib. Damaged financial or medical PDFs never leave your device.