# EPUBCheck RSC-010: link to a non-content file, how to fix it

Source: https://epubcc.com/epubcheck/rsc-010/ (updated 2026-11-04)

EPUBCheck RSC-010 is an error message: “Reference to non-standard resource type found.” A hyperlink points to a file that is not a document a reading app can display, such as a plain image or another non-content file inside the EPUB. Links must lead to content documents (XHTML or SVG).

- Official message (EPUBCheck 5.4.0): Reference to non-standard resource type found.
- Default severity: Error

## Typical causes

- A link to an image file instead of to the page that shows it.
- A link to an embedded file such as a PDF or text file.
- Image links kept from a web page (click to enlarge).

## How to fix it

1. Point the link at an XHTML document that contains the image or content.
2. Or remove the link if readers cannot open the target anyway.
3. Validate again.

## When it's not this

If the target is a content document that is not in the spine, the error is RSC-011.

## Sources

- EPUB 3.3, §3.1.3 The content plane: https://www.w3.org/TR/epub-33/#sec-content-plane (read 2026-11-04)

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