EPUB won't open, is "invalid", or has an empty or broken table of contents
Last reviewed 2026-09-19
An EPUB is a ZIP of web pages plus a package file (the .opf) that lists every file and the reading order, and a contents list. Readers refuse a book when those lists disagree with the files that are really inside, and show a blank contents page when its links point at chapters that no longer exist.
Messages you might see
- “Invalid EPUB file / Could not open book”
- “The table of contents is empty or chapter links do nothing”
Why it happens
- Chapter files were renamed, merged or deleted without updating the package or the contents list.
- The mimetype file is missing or compressed, which strict readers reject.
- The download was cut off, or an editor wrote invalid XML into the package.
Try this first (free, no tool needed)
- Try a second reader (Calibre's viewer, Apple Books, Thorium) because tolerance varies a lot.
- In Calibre, add the book and use Convert books to EPUB or MOBI; the conversion often rewrites a clean structure.
- Re-download the book from the store or source in case the copy was cut off.
If that didn't work
These tools run in your browser. Your file is read and repaired on your own device and is never uploaded.
Broken EPUB Repair
For a book that will not open: writes a correct mimetype, repairs the container and package files, rebuilds the manifest and reading order from the files actually present and repairs damaged XML.
Open Broken EPUB RepairCorrupted ePub Table of Contents Repair
For a blank or broken contents list: checks every entry against the real chapters and anchors, repoints or removes bad ones and rebuilds the list from the reading order when it is empty. Chapter titles of a rebuilt list come from each chapter's first heading, which may not match the author's wording.
Open Corrupted ePub Table of Contents RepairCommon questions
Does this change the book text?
No. Neither tool edits the text of the chapters, only the lists and structure around them.
Is my file uploaded anywhere?
No. The tool runs as a program inside your own browser, so the file is read and repaired on your device and never sent to a server.