Kindle Unlimited Books can't be Downloaded via USB

Obviously, Amazon is making it more difficult to remove DRM from purchased Kindle ebooks. Amazon just changed their encryption scheme again, such that any book published in 2023 or newer is using a new KFX format that is as of yet uncrackable by DeDRM tools. Users can downgrade the Kindle app to skip the KFX format before, however, this new change requires users to update the Kindle app in order to download the content. The good news is that you are still able to remove Kindle DRM if you can download Kindle books via USB if you have a Kindle e-Ink device. This solution is only limited to your purchased Kindle books.

The bad news is that all Kindle Unlimited books are no longer available to download or transfer by USB due to the new KFX format. Amazon even updated the Kindle Unlimited help page on their website with the following:

Note: Borrowed titles can be delivered to and accessed on WiFi-enabled Kindle devices or through the Kindle app, but they cannot be downloaded or transferred via USB.

If this particular limitation applies only to loans, it may be to protect borrowed books from being stripped of DRM. It makes sense. Because you don't own any of this content, it is just lent to you for the duration of an active subscription.

If you don’t want your purchased Kindle books being forever locked into Amazon’s ecosystem, it would be wise to make backups of all your Kindle ebooks in AZW format in case Amazon eventually transitions everything to KFX format with unbreakable DRM.

Newly Published Kindle Files can't be Downloaded via the Older Versions of Kindle Apps

Since Amazon has adopted the KFX format, there’s no DRM Removal tool that can handle Kindle KFX files. Therefore, in order to skip the KFX format, you need to downgrade the Kindle app to an older version to be able to remove Kindle DRM. However, as of today, newly published books seem to be affected. Your Kindle for PC/Mac requires the latest version to download and view the content. Of course, you can still download older books via the older version of Kindle for PC/Mac. 

Luckily, Downloading & transfer via USB targeted to an e-ink Kindle still works even for the newly published ones. 

Here’s a step-by-step guide to help you remove Kindle DRM by downloading Kindle books through Download & transfer via USB method from the Amazon website.

This guide works for both Windows and macOS users. The bad news is that you can't use this method if you don't have a Kindle e-Ink device.