EPUB 3 Error in EPUBCheck version 4.1.1.

[Bjorn G]

Hello everyone, I am new to this forum and community. I am an Indi amateur publisher in the process of creating an EPUB file for 'publishing. I am using Calibre 3.41.3 to produce an EPUB 3 for submission of a book to IngramSpark that requires EPUB 3 format (won't accept EPUB 2).

When checking the EPUB 3 file with "EPUB Validator (beta)" at http://validator.idpf.org/application/validate I get the following message:

WARNING - content.opf: XHTML Content Document file name 'index_split_000.html' should have the extension '.xhtml'.

These errors appear at every page break in my source document (docx format). There is a footnote on the results page that reads - Validated using EPUBCheck version 4.1.1. (an EPUB 2 file from the same input file passes without any errors).

Is there a setting in Calibre that overcomes this problem with the extension file name?

[Doitsu]

Originally Posted by Bjorn G

Is there a setting in Calibre that overcomes this problem with the extension file name?

Open the file with the Calibre editor, highlight all .html files, right-click them, select Change file extension for the selected files, enter xhtml and click OK.

[Bjorn G]

Originally Posted by Doitsu

Open the file with the Calibre editor, highlight all .html files, right-click them, select Change file extension for the selected files, enter xhtml and click OK.

Thanks Doitsu - will do when back at my desk.