# PKG-008: file inside EPUB unreadable, how to fix it

Source: https://epubcc.com/epubcheck/pkg-008/ (updated 2026-11-04)

EPUBCheck PKG-008 is a fatal error message: “Unable to read file "…".” EPUBCheck could not read one of the files inside the EPUB, so it stops checking that file. It is a fatal error: the message names the file, and the rest of what depends on that file cannot be validated.

- Official message (EPUBCheck 5.4.0): Unable to read file "%1$s".
- Default severity: Fatal error

## Typical causes

- The entry is damaged inside the ZIP, often after a truncated download or an interrupted save.
- The entry uses a compression method or encryption that the ZIP reader cannot handle.
- The file was locked or removed while EPUBCheck was reading an unpacked folder.

## How to fix it

1. Note the file named in the message and check that it opens on its own after unzipping a copy.
2. Replace the damaged file from the book's source.
3. Rebuild the archive with a standard ZIP tool (stored or deflate compression only): 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).
4. Run EPUBCheck again on the rebuilt file and fix any message that appears next: a damaged archive can hide other problems until it can be read.

## When it's not this

If the whole archive cannot be opened, that is PKG-003 or PKG-004, not one unreadable file.

## Sources

- EPUB 3.3, §4.3.2 ZIP file requirements: https://www.w3.org/TR/epub-33/#sec-zip-container-zipreqs (read 2026-11-04)

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