# EPUBCheck OPF-034: document twice in spine, how to fix it

Source: https://epubcc.com/epubcheck/opf-034/ (updated 2026-11-04)

EPUBCheck OPF-034 is an error message: “The spine contains multiple references to the manifest item with id "…".” The spine lists the same manifest item more than once. EPUB allows each document to appear only once in the reading order, so a duplicate makes the book invalid.

- Official message (EPUBCheck 5.4.0): The spine contains multiple references to the manifest item with id "%1$s".
- Default severity: Error

## Typical causes

- A chapter added twice by a tool or by hand.
- Books merged from several sources, where the same file ended up in the spine twice.
- A copy-paste of an itemref line that was never changed.

## How to fix it

1. Find the id EPUBCheck names in the spine.
2. Delete the duplicate itemref, keeping the one in the right reading position.
3. If you really need the same content twice, make a copy of the file with its own manifest item.

## When it's not this

If the same file is declared by two manifest items, that is OPF-074.

## Sources

- EPUB 3.3, §5.7.2 The itemref element: https://www.w3.org/TR/epub-33/#sec-itemref-elem (read 2026-11-04)

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