How to Fix NavMap and TOC Errors in EPUB Export

[Madeline5E68]

I'm trying to make a reflowable epub file for an ebook, and no matter what I do, when I check the epub file, I keep getting these two errors:

ERROR(RSC-005): /OEBPS/toc.ncx(16,11): Error while parsing file: element "navMap" incomplete; missing required element "navPoint"

ERROR(RSC-005): /OEBPS/toc.xhtml(9,9): Error while parsing file: element "ol" incomplete; missing required element "li"

It looks exactly how it's supposed to in my epub viewer, so I don't know why I'm getting these. Messing around with the file and searching for solutions online has just made me more frustrated, especially since I know I made an error-free epub last year for a different book - I just don't remember how I did it. I think the problem might be with the TOC, but I don't know what else I can try to get rid of these errors. Any suggestions? I don't have time to try starting over in a different program, since my publication deadline is coming up pretty soon. Could I just make a linked TOC manually instead of using the auto-TOC tool? I honestly wouldn't mind doing that.

<TItle renamed by MOD>

[James Gifford—NitroPress]

First, what EPUB viewer are you using?

Second, what EPUB validator?

First', know that validator results are not nearly as important as they once were — when the approach was to hand-build EPUB files like some kind of programming project, there were many points at which mistakes could be made and validation was an essential tool to find these faults. In these days of exporting EPUB on a level with, say, PDF, checking for every technical jot and niddle is not necessarily useful, or necessary. Sometimes there are actual faults that might affect an end reader; other times the fault are akin to a beautiful new car that drives like a dream... but is 0.1 inch short of factory spec. The final "validation" is if the book reads, renders and navigates properly in a standard EPUB reader.

Second', Since those are ERRORs and not info/warnings, it's probably worth chasing them down.

So, Third —

• Have you created a unique TOC 'style' for the dynamic (reader) table of contents? (That is, not "[default]"?)
• Have you updated this TOC as a last step before export?
• Do you specify this TOC 'style' in the export menu?
• Are you using an in-text TOC as well as the reader/dynamic one?

[Madeline5E68]

1. The file is being checked by the publishing platform itself, Draft2Digital, so I cannot move forward with publication until their built-in checker says the file is okay. I'm not sure if they use their own original checker or have embedded some other one.

3. a. I have not made a TOC style. Not sure I've ever done that before and not sure how I'd do it, but I'll look into that.
b. I did the TOC last, but for some reason the "update" option was grayed out.
c. Since I don't have a TOC style, I have not specified anything in the export menu
d. The TOC appears in the text itself, with clickable links to take you to each chapter, like any other ebook, so not sure what you mean by in-text vs. reader/dynamic one.

[Madeline5E68]

I'm viewing it in Calibre

[James Gifford—NitroPress]

Okay, all very good. (All too often, these sometimes non-problems start with third-rate tools and platforms.)

I'd say all the problems come down to not properly defining the TOC. Try this:

• Create a TOC that contains all the levels you want, properly sorted.
• Set each level to "No Page Number" and "None" style where not grayed out.
• Be sure to check Create PDF Bookmarks (this may be voodoo but won't hurt).
• Be sure teo check Make Text Anchor in source.
• SAVE the TOC under a unique name like EPUB or EBOOK.
  • Repeat the save ANY time you open the TOC panel and make any changes, or they will be lost — and before you click OK to generate the new TOC!
• Click OK.
• Use the loaded cursor to drag out a small text box, pretty anywhere. Then delete the box. (Another voodoo step; you can hit Esc but I have always felt completing the overall operation was more reliable even though no text box/content is wanted for an EPUB.)
  • Repeat the TOC update any time you make changes to the file — not just if you change headings, but because editing might have deleted or moved the text anchors.
• At export time, be sure to select Navigation TOC: Multi Level, and specify your created TOC style name.

Despite the thinking that it's "like any other e-book," in-text TOCs are an anachronism and an eyesore besides being of little use when a dynamic TOC (which can be much deeper in levels) is just a tap away. I'd omit the visible TOC. If you insist on using it, you will need to create a second TOC style, define it all as you like, and save it under a unique name (VISIBLE or ONSCREEN, etc.). Be sure you completely replace any default/existing TOC and update this one, too, separately, as a last step before export. But really — just delete it. Screen TOCs are just clutter in e-books.

That should fix the errors, which are (almost certainly) coming from incomplete update and use of the default style. There is never a need, any more, to edit exported EPUBs. If you have errors, they're in the source or export and should not be patched up with antiquated methods afterwards.

[James Gifford—NitroPress]

For reference —

This should be much the same for both TOC types; DON'T specify page numbers in the in-text one, either.

[Madeline5E68]

I just made a TOC style and it did solve the errors. The TOC style window looked familiar, so I must have done that with last year's book. Only issue now is that the fonts for epub files are automatically encrypted by InDesign and according to Draft2Digital, that could delay or prevent publication at some stores. It won't prevent me from moving forward, but it could cause severe delays or limit my possible sales channels. I'm working on that now - apparently finding the epub's folder and replacing the font files in that folder with the original ones can solve that, but I'm using fonts from Adobe Fonts so I don't think I'd have the original files. I'm going to try some different options to see if there's any chance of preserving my chapter title formatting without bringing those errors back. I know it's possible - I've seen it in other people's ebooks.

[James Gifford—NitroPress]

Don't spec or embed fonts. That's another archaic practice, and nearly all readers will override the selections by default anyway. Reduce the clutter, reduce the hassles, reduce the file size by not embedding fonts; simplify the book by not specifying them, either. (If you don't want to go to more advanced methods, just specify very generic serif and sans-serif fonts like Times and Arial, and uncheck 'Embed Fonts' at export.)

It's a matter of respecting the medium. It's not print. You don't have control of how a reader or user will set the rendering, so don't try.

[Madeline5E68]

As far as I know, the embedding is automatic. How do I get it to export without embedding?

[Madeline5E68]

I also don't know what you mean by spec

[Madeline5E68]

Never mind, I found an option to not embed. I'd still like to preserve the chapter heading look, though. Maybe with an image. I think some ebooks I've read have done that.

[James Gifford—NitroPress]

Again — you have little control over how a reflowable EPUB appears to any particular user, on any particular reader, and since you're going through D2D, the end user could have any of the dozens of readers out there. (Unlike, say, Kindle or Apple.) So getting picky over fonts and such, as for print, is largely wishful thinking for e-books, and carries more problems and unnecessary baggage (literally, in the embedded font data, which can out-bulk the actual book content) than it's worth.

You can do an extraordinary amount with four serif and four sans faces, size, color, graphic elements and such. Fussing with the font doesn't bring much else.

But, if you really-really want your fancy title page or chapter headings, you can do with with graphics instead. Not a pefect solution, especially as graphics don't adapt to a reader background (sepia, green, gray, black) but better overall than trying to force font choices.

[James Gifford—NitroPress]

It's hard to avoid in InDesign unless you use a CSS file to null it out, but you "spec" — specify fonts inherently with styles. (At the CSS level, it's easy to reduce these to generic types like serif, sans-serif, monospace, etc., and that eliminates ALL downstream font issues.)

InDesign embeds the fonts in the exported file by default unless you UNCHECK the "Include Embeddable Fonts" box in the HTML/CSS pane of the export menu —

Embedding is only inherent/required for fixed-page export (FXL), which shouldn't be used for text-based books anyway.

[Madeline5E68]

Yeah, I know my options are limited and the reader has a lot of design control, but I know it's possible to have an epub with a clickable TOC and chapter headers that are images instead of text - I've read many ebooks that are like that. I tried a few methods and haven't found a way to make it work, so I'm just going to have to deal with the chapter headers being changeable by the reader. I don't like that, since I've seen that it's possible to preserve the appearance (maybe just not in InDesign, I don't know), but I'm not going to keep working on this issue when I have a file that works and I'm on a deadline. I've preserved as much of the design as I can without causing issues with the file. Thanks for all your help with this.

[James Gifford—NitroPress]

Okay, and all good. I'll just note that there are a lot of e-books out there I wouldn't use as a model or standard(-practice) of anything.

Digital isn't print; respect the medium. I'll leave it at that.