Repair Corrupt PDF
Recover and fix corrupted or damaged PDF files that won't open in standard viewers. The repair engine reconstructs broken internal structures including damaged cross-reference tables, missing end-of-file markers, and corrupt object streams. While it cannot restore content that is physically missing from the file, it can often recover accessible data from otherwise unreadable documents.
What does this tool do?
The Repair tool attempts to reconstruct damaged PDF files using MuPDF's robust parsing and recovery capabilities. It addresses common corruption issues: broken xref (cross-reference) tables that prevent page access, missing %%EOF markers, truncated object streams, malformed object declarations, and orphaned data streams. The tool re-parses the file from scratch, identifies recoverable content, rebuilds valid internal structures, and produces a new PDF with accessible content.
How it works
Using MuPDF's lenient parsing mode, the tool reads the corrupted file byte-by-byte, identifying PDF object signatures, stream data, and structural markers. It builds a new valid xref table by scanning for all objects in the file. Missing structural elements are recreated according to PDF specification requirements. Content streams are validated and repaired where possible. The recovered objects are then written to a new PDF file with correct structure, allowing standard PDF viewers to open the document.
Features
- Rebuilds corrupt xref tables for object access
- Repairs missing %%EOF markers
- Recovers truncated and malformed object streams
- Removes duplicate object IDs causing conflicts
- Garbage-collects orphaned data streams
- Preserves recoverable content and structure
- Creates a new valid PDF from damaged source
How to use
- 1
Upload the corrupted PDF
Drag the broken PDF that fails to open or shows errors onto the drop zone. The tool analyzes the file structure to assess recoverability.
- 2
Initiate repair process
Click Repair PDF. MuPDF re-parses the file from scratch, scanning for all recoverable objects and content streams. This may take a moment for large files.
- 3
Review recovery results
The tool reports how many pages and objects were recovered. A preview shows the first recovered page if available.
- 4
Download repaired file
Save the repaired PDF. Open it in your standard PDF viewer to verify the recovery. Some content may be missing if it was physically corrupted in the original file.
Common use cases
Recover files from failed transfers
PDFs corrupted during interrupted downloads, incomplete email attachments, or failed cloud syncs can often be repaired to recover accessible content.
Fix storage media damage
Files from failing hard drives, damaged USB drives, or corrupted storage media that produce read errors may have recoverable portions restored.
Repair legacy PDFs
Older PDFs created with obsolete software or non-standard encoders that modern viewers cannot open may be recovered into standard-compliant documents.
Salvage content after software crashes
PDFs left in an inconsistent state after application crashes or system failures during editing can often be reconstructed.
Tips & best practices
- Repair cannot restore content that is physically missing from the file — it only reorganizes existing data into a valid structure
- If the repair produces a partial document, extract the recoverable pages immediately and save them as a new file
- For encrypted PDFs, you must decrypt first using the Password tool before repair can access the content
- Some corruption may be invisible — always verify repaired files by viewing all pages before discarding the original