Error read while uploading to SIGIL
 

Can someone help? This is my 1st epub conversion. I'm not at all advanced with understanding error codes.
These are the codes I got after validating:
ERROR OEBPS/content.opf 7 14 Error while parsing file: element "metadata" incomplete; missing required elements "dc:language" and "dc:title"
ERROR OEBPS/content.opf 8 13 Error while parsing file: Exactly one manifest item must declare the 'nav' property (number of 'nav' items: 0).

BTW: those were "Line 7 position 14" and Line 8 position 13" errors

HERE IS MY Content.opf:
<?xml version="1.0" encoding="utf-8" ?>
<package prefix="rendition: http://www.idpf.org/vocab/rendition/#" unique-identifier="BookId" version="3.0" xmlns="http://www.idpf.org/2007/opf">
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:opf="http://www.idpf.org/2007/opf">
<dc:identifier id="BookId">urn:uuid:92f30da8-6af6-40fc-9de7-4dc7f73f68ae</dc:identifier>
<meta content="0.9.3" name="Sigil version"/>
<meta property="dcterms:modified">2019-04-18T14:00:43Z</meta>
</metadata>
<manifest>
<item href="toc.ncx" id="ncx" media-type="application/x-dtbncx+xml"/>
<item href="Text/Section0001.xhtml" id="Section0001.xhtml" media-type="application/xhtml+xml"/>
</manifest>
<spine toc="ncx">
<itemref idref="Section0001.xhtml"/>
</spine>
</package>

In Sigil's Tools menu is Metadata Editor; select that. Then in the window it brings up click the Add Metadata button and add the correct information. Try it on a new file to see how it works.

Some metadata is required, like language and title. You must enter that metadata. The easiest method is the one lumpynose described.

Still having problems.
 

Thank you lumpynose and Toxaris for your help. I tried to fix same problem but got hung up due to lack of experience. When I tried to click "Add Metada" button, it said that it was not yet avail for epub3 which is what I need for publishing on IngramSpark. It directed me to add the info manually. Only problem is I don't know where to add that and what to add. Can you help with this more elementary question? I'd be so grateful. I just have this final step to publish my book. I've struggled thru everything else til now but am stumped!

Then you're using a terribly outdated version of Sigil. The ability to edit epub3 metadata with the metadata editor has been around for a long time. Update your Sigil.

https://www.mobileread.com/forums/sh...d.php?t=210791

You use Sigil 0.9.3 – released 31 January 2016 – so in this old version it will not work.
Use newest release (0.9.13) from here.

Error read while uploading to SIGIL
 

BeckyeBook: thank you. That did work. Now I'll have to see if IngramSpark accepts it. They made a big deal out of making sure it is an epub3 NOTHING ELSE. Newest version of Sigil returned an epub3.1. Fingers crossed. TY for taking the time to respond and all others too!

Error read while uploading to SIGIL
 

Thank you. I used the outdated based on info I received to qualify for IngramSpark. But, I may have misunderstood them. Now have updated version and will see if Ingram accepts. TY!

The new version will certainly make sure that the missing metadata items are present. It won't, however guarantee that the default values for those items will be correct. You'll still need to edit them.

My point is that it's not really Sigil (let alone a specific version of Sigil) that determines whether or not an EPUB will validate without any errors. That will ultimately be the responsibility of the user. Always. Sigil is not (nor is it intended to be) a complete turn-key solution for EPUB creation/production. Some knowledge of EPUB construction is always going to be a requirement to successfully produce an EPUB with Sigil that passes a particular vendor's submission rules.

I'll be damned if I know wht the Hades is up with IS. We've been sending them ePUB2.0 ePUBs for the last nth years, and they accept them without comment. Their own specs, last I looked, said ePUB 2.0, not 3.x.

Hitch

No version of Sigil returned any version "3.1". If that is what the opf package tag version attribute shows, it did not come from Sigil.

This does not appear to be a Sigil specific issue at all. Questions about epub3 structure should really be part of the epub forum on MR and not Sigil.