# EPUBCheck PKG-004: Corrupted EPUB ZIP header

Source: https://epublab.com/epubcheck/pkg-004/ (updated 2026-11-03)

EPUBCheck PKG-004 is a fatal error message: “Corrupted EPUB ZIP header.” The ZIP structure of the EPUB is damaged, so EPUBCheck cannot list or read its files.

- Official message (EPUBCheck 5.4.0): Corrupted EPUB ZIP header.
- Default severity: Fatal error

## Typical causes

- A truncated download or transfer.
- A tool that wrote the ZIP incorrectly or was interrupted while writing it.

## How to fix it

- Get a fresh copy of the EPUB or export it again from its source.
- Rebuild the archive with the mimetype file first and stored uncompressed, for example from the folder that contains the book: zip -X0 book.epub mimetype and then zip -rX9 book.epub META-INF OEBPS (use your own folder names).

Message text and severity: EPUBCheck (W3C, BSD-3-Clause). Explanation: EPUBLab.