At this time, we're investigating the problem and looking for a solution.
If you've encountered this issue while converting your file, we suggest attempting to create and upload an EPUB directly to our system.
While there are a number of EPUB conversion options, Calibre (Download Here) has shown the best results for creating an EPUB for the Lulu system. Please review their extensive Help resources (Found Here) to create an EPUB 2 that our system can validate.
We've also created this Forum Thread. Post questions here and we'll do our best to respond and assist.
eBooks in Microsoft Store?
With the Windows 10 Creators Update that's expected to be rolled out starting today (April 11, 2017), Microsoft is adding eBooks to the Microsoft Store. This will give them the ability to sell eBooks, similar to eBook sales channels offered by Google and Apple.
I've been searching, trying to find out how they're sourcing their eBooks. Does anyone know? Is it a partnership with Barnes & Noble? Are they working directly with publishers? I haven't been able to find any info at all about self-publishing eBooks for sale on Microsoft Store.
And does Lulu have plans to support Microsoft Store as a sales channel? I use Lulu to sell through Apple and Barnes & Noble, and it would be convenient if we could pay a fee, check a box, and add Microsoft Store to the list.