PDF XRef Repair Utility
Scan object byte offsets, adjust faulty startxref values, clean duplicate incremental update indexes, and synthesize valid cross-reference tables offline.
How PDF XRef Repair Works
Diagnose offset issues and reconstruct cross-reference table markers in 3 steps.
Upload PDF
Drag your PDF file in. The byte stream buffer is read directly inside your browser memory.
Analyze Offsets
The repair engine matches declared XRef offsets against physical byte address positions.
Recompile Table
It synthesizes a new standard xref dictionary and rewrites the startxref keyword offset.
Restore broken file layout trees and offset tables
Correct pointer shifts, remove corrupted incremental revisions, and flatten data streams locally.
Physical Offset Inspection
Cross-checks declared indices with scanned stream start addresses to detect shifting.
Incremental Block Removal
Flattens historical update revision logs to keep only the newest objects, reducing file bloat.
Confidential Local Mode
PDF repair is performed completely in client sandbox memory. No file data leaves your machine.
Frequently Asked Questions
Common questions regarding cross-reference repairs and byte offset mappings.
Q.What is a PDF cross-reference (XRef) table?
The XRef table maps direct object IDs to their precise byte-offset positions inside the file structure. This enables reader applications to find objects quickly without parsing the whole file.
Q.How do byte offsets get shifted or corrupted?
Saving a PDF outside standard editors, downloading via binary-hostile networks, or concatenating blocks arbitrarily can add or modify hidden bytes, shifting all subsequent physical offsets.
Q.What does "Flatten & Clear updates" do?
PDF revisions append changes incrementally to the file footer. Flattening isolates the newest revision of each object, removes the older iterations, and compiles a single simplified catalog.
Q.Is my data transmitted online during the repair?
No. All forensic scanning, index recompilation, and stream generation happen entirely locally in the browser sandbox. No bytes are sent to external servers.