# EPUBCheck RSC-030: File URLs are not allowed in EPUB, but…

Source: https://epublab.com/epubcheck/rsc-030/ (updated 2026-11-03)

EPUBCheck RSC-030 is an error message: “File URLs are not allowed in EPUB, but found "…".” A file: URL points to a file on someone's computer; EPUB does not allow file URLs.

- Official message (EPUBCheck 5.4.0): File URLs are not allowed in EPUB, but found "%1$s".
- Default severity: Error

## Typical causes

- Links or images that still point to the author's disk, such as file:///C:/Users/… after export.

## How to fix it

- Add the resource to the EPUB and reference it by a relative path, or remove the reference.

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