enter image description hereI get these two errors:

ERROR(RSC-005): Error while parsing file 'attribute "epub:type" not allowed here;

ERROR(RSC-005): Error while parsing file 'element "aside" not allowed anywhere;

How can I remove them? I want to use pop-up footnotes with epub3.

Regards Dan

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    – babou
    Commented Oct 28, 2018 at 11:18

2 Answers 2


epub:type attributes can only be used in epub3 books. You'll need to select Polish books > Upgrade book internals to convert your epub2 book to an epub3 book.

  • Thank you Nemo, this solution worked fine.
    – Dan
    Commented Oct 27, 2018 at 3:03
  • Under the updated version, (mine is version 6.8.0 now), I go to: Tools > Upgrade book internals Commented Nov 13, 2022 at 8:54

A quick fix on top of "Tools > Upgrade book internals" is to add the following HTML attribute for html files that uses "epub:type"

<html xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://www.idpf.org/2007/ops">

Do take note that after you did the "Upgrade book internals" once, your subsequent HTML files will not have the xmlns:epub attribute. Running "Upgrade book internals" again will still give you the error as the xmlns:epub attribute is not added into the new HTML file. Hence, it is good to paste manually.

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