Repair PDF

A PDF is more like a tiny filesystem than a single document. It has objects (text, fonts, images, pages) and an index (the "cross-reference table" or xref) that says where each object lives in the file. When a PDF gets corrupted — interrupted download, faulty USB transfer, partial copy, bad email attachment — the xref usually breaks first. Without the xref, viewers cannot find the pages and show "this file is damaged."

SwitchPDF's repair pipeline walks the raw bytes of the file from start to finish, identifies every object it can recognize (by signature: dictionaries start with "<<", streams have "stream...endstream" markers, etc.), and rebuilds the xref from scratch using the actual positions it found. It then validates the page tree, checks that all referenced fonts and images exist, and writes a clean PDF.

Recovery success depends on how much of the file survived. Truncated downloads (where the end of the file is missing) often recover everything up to the truncation point. Corrupted xref tables almost always recover fully. Files that have been overwritten or have damaged content streams may only recover partial pages — but partial is usually better than nothing.

The tool is non-destructive: it never modifies your upload, only produces a new PDF as the output. If repair finds nothing salvageable, you will get an error message rather than a blank file. This is the same approach Adobe Acrobat uses internally when it "rebuilds" a PDF on open.