# EPUBCheck PKG-011: file name ending in a dot, how to fix it

Source: https://epubcc.com/epubcheck/pkg-011/ (updated 2026-11-04)

EPUBCheck PKG-011 is an error message: “The file name "…" is not allowed to end with ".".” A file name inside the EPUB ends with a full stop, which the EPUB container rules forbid. Some operating systems strip a trailing dot, so the file would no longer match the references to it.

- Official message (EPUBCheck 5.4.0): The file name "%1$s" is not allowed to end with ".".
- Default severity: Error

## Typical causes

- A file saved without an extension after a name that ends in a dot, or a tool that trimmed the extension.
- Names built from sentences or abbreviations, such as "Fig. 1.".

## How to fix it

1. Give the file a proper extension (for example .xhtml, .jpg or .css).
2. After renaming, update every reference to the file: the manifest in the package document, links and image sources in the XHTML, and url() references in the CSS.
3. Rebuild the archive and validate again.

## When it's not this

Other forbidden characters in a name are reported as PKG-009.

## Sources

- EPUB 3.3, §4.2.3 File paths and file names: https://www.w3.org/TR/epub-33/#sec-container-filenames (read 2026-11-04)

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