# PDF Repair Enhanced Advanced PDF repair with detailed diagnostics, before/after comparison, and repair logging > Canonical page: https://elysiatools.com/en/tools/pdf-repair-enhanced - **Category:** PDF Tools - **Keywords:** pdf, repair, corrupt, diagnostic, analyze, recover, health, 诊断, 修复 ## Overview Enhanced PDF repair tool with comprehensive diagnostics and reporting. **Features:** - Detailed diagnostic report showing file health score and specific issues - Before/after comparison (MD5, size, page count, object count) - Complete repair log with timestamp and method used - Multiple repair engines (qpdf, pdf-lib, Ghostscript) **Diagnostic Categories:** - Header validation and version detection - Page count and structure verification - XRef and trailer integrity check - EOF marker validation - Encryption detection - Overall health score (0-100) **Repair Strategies:** 1. Header normalization (recover misplaced or missing %PDF- header) 2. qpdf rebuild (object table and xref reconstruction) 3. pdf-lib rewrite fallback for mildly damaged structure 4. Ghostscript rewrite fallback ## Inputs - **Source PDF File** (file): Upload potentially damaged PDF ## When to use - When a PDF file fails to open in standard readers due to a corrupted header, missing EOF marker, or broken cross-reference (XRef) table. - When you need to run detailed diagnostics on a suspicious PDF to check its structural health score and encryption status. - When standard PDF repair tools fail and you require multi-engine fallback strategies to recover document pages. ## How it works - Upload the damaged or corrupted PDF file to the secure processing interface. - The tool runs diagnostic checks to validate the PDF header, verify page structure, and inspect the XRef table and trailer integrity. - If issues are detected, the system sequentially applies repair strategies, starting with header normalization and qpdf rebuilding, falling back to pdf-lib and Ghostscript rewrites if necessary. - The repaired PDF is generated along with a detailed diagnostic report, health score, and before/after comparison metrics. ## Use cases - Recovering corrupted business reports that show 'Failed to load PDF document' errors in web browsers. - Auditing damaged PDF archives to generate structural health scores and repair logs before ingestion into a database. - Fixing broken PDF headers and missing EOF markers caused by incomplete file transfers or interrupted downloads. ## Frequently asked questions ### What repair engines does this tool use? The tool utilizes qpdf for rebuilding object tables, pdf-lib for structural rewrites, and Ghostscript as a fallback engine for severely damaged files. ### Can I see what was fixed in my PDF? Yes, the tool provides a detailed repair log and a before-and-after comparison showing changes in file size, page count, object count, and MD5 hashes. ### What is the maximum file size supported for repair? You can upload and repair PDF files up to 500 MB in size. ### How does the tool calculate the health score? The health score (0-100) is calculated based on header validation, page structure verification, XRef table integrity, and EOF marker presence. ### Does this tool support repairing encrypted or password-protected PDFs? The tool detects encryption during diagnostics, but encrypted files cannot be structurally rebuilt without the correct decryption credentials. ## Related tools - [PDF Repair Corrupt](https://elysiatools.com/en/tools/pdf-repair-corrupt): Attempt to repair damaged PDF headers and broken/missing XRef tables - [Data URI Generator](https://elysiatools.com/en/tools/data-uri-generator): Convert files into Data URIs (Base64 or percent-encoded) for inlining images, fonts, and assets directly into HTML, CSS, or Markdown - [PDF Batch Compress](https://elysiatools.com/en/tools/pdf-batch-compress): Compress multiple PDF files with image downsampling and optimization, packaged as ZIP - [PDF Batch Watermark](https://elysiatools.com/en/tools/pdf-batch-watermark): Apply text watermarks to multiple PDF files with rotation, opacity, and tiling options - [PDF Form Fill Batch](https://elysiatools.com/en/tools/pdf-form-fill-batch): Fill one PDF form template with an array of records and output one filled PDF per record (ZIP) or a merged PDF - [PDF Merge Documents](https://elysiatools.com/en/tools/pdf-merge-documents): Merge multiple PDF files with optional table of contents and separator pages - [PDF Optimize Advanced](https://elysiatools.com/en/tools/pdf-optimize-advanced): Advanced PDF optimization: remove metadata, clean structure, and recompress content - [PDF Rasterize Pages](https://elysiatools.com/en/tools/pdf-rasterize-pages): Render PDF pages into high-fidelity image sequences (PNG/JPG/WebP) with configurable DPI and page range ## Samples - [PDF Samples](https://elysiatools.com/en/samples/pdf-samples): Generated PDF samples from tools dated 2026-02-01 to 2026-02-10 - [Markdown Slide Deck Samples](https://elysiatools.com/en/samples/md-slide-deck-to-pdf): Remark/Marp style Markdown slide decks for testing PDF export layouts - [Time Zone Workflow Scheduler ICS Samples](https://elysiatools.com/en/samples/time-zone-workflow-scheduler-ics-samples): ICS files generated in the same structure returned by the Time Zone Workflow Scheduler, with multiple VEVENT meeting candidates exported from overlap windows - [ASS Subtitle Samples](https://elysiatools.com/en/samples/ass-samples): Sample ASS subtitle files from simple to complex for style-aware subtitle parsing, translation, conversion, and localization QA ## Related content - [PDF Repair, Cleanup, and Slimming](https://elysiatools.com/en/hubs/pdf-repair-cleanup-and-slimming): Rescue a damaged PDF, strip what should not travel with it, and cut its weight — repair broken headers and cross-reference tables with diagnostics, export annotations before erasing them, remove metadata and form fields, then downsample and recompress to hit your size target.