UtilityKit

500+ fast, free tools. Most run in your browser only; Image & PDF tools upload files to the backend when you run them.

PDF Repair

Best-effort recovery of corrupt or unreadable PDFs by re-parsing and re-saving

About PDF Repair

PDF Repair attempts to recover a damaged or partially corrupt PDF that fails to open in normal readers. The tool loads your file via pdf-lib in lenient mode, traverses the object tree, resets the metadata, and writes a fresh, well-formed PDF — often re-emitting object streams to compact and de-duplicate. This works for common damage classes: truncated downloads, broken cross-reference tables (xref), partially-corrupted metadata, files saved by buggy generators, or PDFs edited by a tool that did not flush properly. It cannot recover files where the actual page content streams are missing or the PDF is encrypted with a lost password. Everything runs locally in the browser — no upload, no server. Always keep the original damaged file before downloading the repaired copy.

Why use PDF Repair

Best-Effort Without Software Install

No need to install qpdf, MuPDF, or Ghostscript locally — everything runs in the browser.

Two-Stage Parse

Strict parse first for clean files, lenient fallback for damaged ones — gives every chance of recovery.

Object Stream Re-Emission

Compacts and rebuilds the cross-reference table, fixing the most common corruption class.

Safe by Default

Always keeps your original — the repaired file downloads as a separate 'repaired' copy.

Live Diagnostic Log

Every step is reported — header check, parse mode, page count, save size — so you understand what the tool actually did.

100% Local

Confidential or sensitive damaged documents never leave your browser, even when broken.

How to use PDF Repair

  1. Upload the damaged or unreadable PDF — up to 50 MB, processed entirely in your browser.
  2. The tool sniffs the file header and reports basic findings in the log panel.
  3. Leave 'Ignore minor errors during parse' on (default) — it lets pdf-lib salvage objects with small inconsistencies.
  4. Leave 'Re-emit object streams' on — this compacts and de-duplicates the saved PDF.
  5. Click Repair PDF — the tool first tries strict parse, then falls back to lenient mode if needed.
  6. If repair succeeds the recovered file downloads automatically; verify by opening it in your normal PDF reader.

When to use PDF Repair

  • When a PDF download was interrupted and the resulting file fails to open with 'corrupt' or 'damaged' errors.
  • When a tool's buggy export produces PDFs that crash Adobe Reader but show fine in other viewers.
  • When a cloud sync (Dropbox, Google Drive) flagged a PDF as broken and the original is no longer available.
  • When merging or editing a PDF in another tool produced a result that fails to open.
  • When you receive a PDF attachment that returns 'PDF structure error' in your reader.
  • Before reporting a bug to a PDF generator vendor — re-save through pdf-lib and see if the issue persists in the cleaned copy.

Examples

Truncated download

Input: report.pdf (1.2 MB) — interrupted Wi-Fi mid-download, fails to open in Acrobat

Output: report-repaired.pdf — pdf-lib re-emits the xref, file opens cleanly with all 14 pages intact

Buggy generator output

Input: invoice.pdf (88 KB) — produced by an old library, opens in Chrome but crashes Preview

Output: invoice-repaired.pdf — clean PDF that opens in every reader, identical visual content

Edited and resaved

Input: manual.pdf (3.4 MB) — edited in three different tools, now flagged as 'PDF structure error'

Output: manual-repaired.pdf — single clean object table, slightly smaller, all pages preserved

Tips

  • Always keep the original damaged PDF until you have verified the repaired copy works in your preferred reader.
  • If repair fails, run the file through qpdf locally: qpdf --check broken.pdf — it gives the most detailed structural diagnostic.
  • Files damaged at the page-content-stream level (missing graphics, missing text) cannot be recovered — only structural damage is repairable.
  • If the damaged file is encrypted, run PDF Unlock first if you have the password; this tool cannot guess passwords.
  • If the result is smaller than the original, the tool likely de-duplicated unused objects — that is normal and the content is still intact.

Frequently Asked Questions

Will every corrupt PDF be repairable?▾
No. PDFs with damaged page content streams (missing text, missing graphics) cannot be recovered — only structural damage like broken xref or metadata is repairable. Roughly 70–80% of 'PDF won't open' errors fall into the repairable category.
Is my file uploaded to your server?▾
Never. pdf-lib runs entirely in your browser, even on damaged files. UtilityKit cannot see the content of your PDF.
What if repair fails?▾
Try qpdf locally with qpdf --check broken.pdf for a detailed diagnostic. Some PDFs are damaged beyond browser-side recovery.
Will the repaired file look identical?▾
Yes — for repairable files, content is preserved byte-for-byte at the object level. Only the xref table and metadata are rebuilt.
Why is the repaired file smaller than the original?▾
The tool de-duplicates unused objects and re-emits compressed object streams — that is normal and the content is intact.
Does this work on encrypted PDFs?▾
Only if you have the password — run the file through PDF Unlock first, then through PDF Repair if the unlocked copy is also damaged.
Can I batch-repair many PDFs at once?▾
Not in the current UI — process them one at a time. For bulk repair, scripting via pdf-lib or qpdf locally is more efficient.
What does 'Ignore minor errors' actually do?▾
It tells pdf-lib to skip over malformed individual objects rather than aborting the whole parse — letting the rest of the PDF be salvaged when one object is broken.

Explore the category

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Glossary

Cross-Reference Table (xref)
A table at the end of a PDF that maps object numbers to byte offsets — the most common corruption point.
Object Stream
A compressed container holding multiple PDF objects together — re-emitting it compacts the output.
Lenient Parse
Loading mode that ignores minor structural inconsistencies and tries to salvage usable objects — what this tool falls back to.
Page Content Stream
The drawing instructions inside a page — if these are corrupted, the visual content cannot be recovered.
Producer
Metadata field naming the tool that wrote the PDF — reset to 'UtilityKit PDF Repair' on the recovered copy.
Truncated File
A PDF that is missing bytes at the end (often the xref table) due to interrupted download — usually repairable.