# EPUBCheck OPF-055: empty EPUB 2 metadata tag, how to fix it

Source: https://epubcc.com/epubcheck/opf-055/ (updated 2026-11-04)

EPUBCheck OPF-055 is a warning message: “… tag is empty.” A metadata element in an EPUB 2 package document is empty, and EPUBCheck names it. Empty metadata gives reading apps and stores nothing to show, so it is reported as a warning.

- Official message (EPUBCheck 5.4.0): %1$s tag is empty.
- Default severity: Warning

## Typical causes

- An empty dc:title, dc:identifier or dc:date left in a template.
- A field exported from a catalogue where the value was blank.
- A value removed by hand without removing its element.

## How to fix it

1. Find the element EPUBCheck names in the metadata section.
2. Fill it with a real value.
3. If you have no value for an optional element, delete it; required ones (title, identifier, language) must be filled.

## When it's not this

In EPUB 3 empty metadata is caught by the schema and reported as RSC-005; other empty Dublin Core elements in EPUB 2 are OPF-072.

## Sources

- 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.