Amazon App Store with some devices won't install apps. It will say downloading then says installing then just does nothing.

This is caused by the MIUI optimization feature.

There are 2 ways of working around this.

The first is to disable the MIUI each time you want to install or update an app through the Amazon App Store or you can use this version of the Amazon app.

I was given this by an Amazon tech support person who is familiar with this Xaiomi issue.

http://amazon.com/appstore_android_app

Hopefully this will work on your device as well fixing the issue.

DO NOT UPDATE THE AMAZON APP STORE app after you install this or you'll end up with the current version and end up with the install issue again.