

Wait a few minutes for it to take effect and try to sign in again. If that occurs go to the Amazon website and on the manage your content and devices page, and on the "Your Devices" tab locate "Kindle for PC" (or Mac) and deregister it using the "." "Actions" menu. Some users have reported being unable to sign in to their Amazon account within Kindle for PC once version 1.17 is reinstalled.

There are several methods for either avoiding or handling KFX format. Unless additional steps are taken, these books will fail to convert in calibre with the error: "KFXError: This is an Amazon KFX book. Each book will appear in a separate subdirectory of the "My Kindle Content" folder with a file extension of ".azw".

The Kindle for PC and Kindle for Mac programs use Amazon's KFX format for most books. There is also a new method (#6) using an old version of the Kindle for Android app described here. (Details in this thread.)This means that methods 1, 2, and 4 described below are no longer effective for those books. Important update: Amazon has made a change to their service so the books published since can no longer be downloaded using Kindle for PC or Mac versions prior to 1.39.
