# RSC-003: no OPF rootfile in container, how to fix it

Source: https://epubcc.com/epubcheck/rsc-003/ (updated 2026-11-04)

EPUBCheck RSC-003 is an error message: “No rootfile tag with media type "application/oebps-package+xml" was found in the container.” META-INF/container.xml exists but none of its rootfile elements has the media type application/oebps-package+xml, so the package document cannot be found. Reading apps rely on that exact value to pick the package document.

- Official message (EPUBCheck 5.4.0): No rootfile tag with media type "application/oebps-package+xml" was found in the container.
- Default severity: Error

## Typical causes

- A misspelled or missing media-type attribute on the rootfile element.
- A container.xml written by hand or copied from a template with another media type, such as application/xml or text/xml.

## How to fix it

1. Open META-INF/container.xml.
2. Set media-type="application/oebps-package+xml" on the rootfile element that points to the package document.
3. Check that its full-path is correct too, rebuild and validate again.

## When it's not this

If the rootfile is right but the file it names does not exist, the error is PKG-020.

## Sources

- EPUB 3.3, §4.2.6.3.1.3 The rootfile element: https://www.w3.org/TR/epub-33/#sec-container.xml-rootfile-elem (read 2026-11-04)

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