# EPUBCheck OPF-033: no linear spine items, how to fix it

Source: https://epubcc.com/epubcheck/opf-033/ (updated 2026-11-04)

EPUBCheck OPF-033 is an error message: “The spine contains no linear resources.” Every item in the spine is marked linear="no", so there is nothing to read from start to end. The spine defines the reading order, and at least one document has to belong to it.

- Official message (EPUBCheck 5.4.0): The spine contains no linear resources.
- Default severity: Error

## Typical causes

- linear="no" applied to all items by mistake, for example with a find-and-replace.
- A tool setting that marks every document as auxiliary content.
- A spine that only lists notes or appendices after the main chapters were removed.

## How to fix it

1. Open the spine in the package document.
2. Remove linear="no" from the itemrefs that make up the main text (linear="yes" is the default).
3. Keep linear="no" only on auxiliary documents such as answer keys or pop-up notes.

## When it's not this

If only some non-linear documents are unreachable, that is OPF-096.

## 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.