Ray McCarthy
Sentient Marmite: The Truth may make you fret.
a) Perhaps a Kindle fireThat didn't work for @Brian Turner Ray
b) Perhaps saved in the wrong place.
I've tested kindle app on several things and ebooks on 4 different generations of real Kindle.
A Kindle Fire isn't a "real" kindle, it's a customised tablet with Amazon apps, I don't know where it expects an ebook to be stored, but the Android tablet I tested needed ebook to be saved where Amazon Kindle App expects it to be. On one Windows version, double clicking on an random located eBook resulted in Kindle app copying it to its preferred eBook location. Later versions of Windows Kindle App use a protected store that they copy it to, so that if you download direct to the Kindle App from Amazon, you can't copy the book to your kindle or make a backup, your other kindle apps / devices have to download it AGAIN from the Amazon Cloud. This is why with limited cap and desire to have backup that if buying from Amazon I pick "deliver to PC", NOT the Kindle App on a PC or actual Kindle.
It's confusing.
The save or copy method only works with .azw, .prc .mobi or pdfs. Anything else needs converted using mobicreator (or Calibre if an ePub) or by email to the Kindle (in which case Amazon uses mobicreator).
[Amazon or MobiCreator actually use a copy of Word or similar to convert Word Doc or DocX to intermediate HTML, as actually all eBooks are really filtered HTML, images, css and database in a single file.]
If you "jailbreak" a physical Kindle (at least in the past) then ePubs work but .azw files with DRM bought from Amazon DON'T open. So don't "jailbreak" a Kindle if you use bought books with DRM rather than Smashwords or Gutenberg!