# CHK-001: custom message file problem, how to fix it

Source: https://epubcc.com/epubcheck/chk-001/ (updated 2026-11-04)

EPUBCheck CHK-001 is an error message: “The custom message overrides file was not found.” EPUBCheck could not use the custom message file passed with -c (--customMessages). CHK-001 means the file was not found, and CHK-002 to CHK-007 report other problems in it. These messages are about that file, not about the EPUB.

- Official message (EPUBCheck 5.4.0): The custom message overrides file was not found.
- Default severity: Error

## Typical causes

- CHK-001: a wrong path to the file, or a file that was moved.
- CHK-002 and CHK-003: a message ID or a severity EPUBCheck does not recognise, from a typo or from another EPUBCheck version.
- CHK-004 and CHK-005: a custom message or suggestion with more %1$s-style parameters than the original; CHK-006: a format parameter that cannot be parsed.
- CHK-007: the file cannot be read or is not in the expected tab-separated format.

## How to fix it

1. Check the path you pass to -c (--customMessages) and that the file exists.
2. To start from a correct file, run EPUBCheck with -l (--listChecks) to write the list of message IDs and their severities, then edit that list.
3. Keep the original placeholders in custom texts and use only the severities the list shows.
4. Or run EPUBCheck without -c to validate with the default severities.

## When it's not this

CHK-008 is different: an error while processing one item of the EPUB, not the custom message file.

## Sources

- EPUBCheck wiki: Running EPUBCheck (command-line options): https://github.com/w3c/epubcheck/wiki/Running (read 2026-11-04)
- EPUBCheck 5.4.0 message texts (MessageBundle.properties, w3c/epubcheck on GitHub): https://github.com/w3c/epubcheck/blob/v5.4.0/src/main/resources/com/adobe/epubcheck/messages/MessageBundle.properties (read 2026-11-04)

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