I also tried downloading file from Amazon. It was working before the upgrade, but when I reinstalled, it no longer removes DRM. You can get that serial number from your Kindle, by clicking on the menu button on top right of home screen, then Settings, then clicking the menu button on top right of screen AGAIN, and then clicking Device Info.Just added Calibre back after computer upgrade. If, like me, you are a Kindle eInk Reader user, you’ll need your Kindle serial number if the information isn’t already there (it was for me). If you highlight plugin and click Customize Plugin button you can check your settings for the various file types. Puzzle piece icon next to it will be green if enabled. It should install and enable the plugin, which you’ll find in the File Type plugins section. In Calibre, click on Preferences, scroll down and click on Plugins in the Advanced section, Click on the “Load plugin from file” button on the bottom right of the Plugins screen. While I have yet to try the latest version of DeDRM with that, the setting I had for that seemed to be still there too, so I’m assuming that will continue to work as before. I occasionally get Adobe Digital Editions ePubs when Kindle format isn’t available. Removing and reloading the book in question showed the DeDRM Pre-Release seemed to do the trick for this book anyway.

I downloaded it and installed the new plugin and it retrieved all my old settings which were apperently still there from the previous version of the plugin. I checked with Aprentice Alf’s Blog and sure enough they have a DeDRM Pre-Release. Apparently the app now uses the Python 3 language for it’s plugins… I only just realized the latest update to the wonderful and long-running and continuously improved Calibre E-book Manager application removed my old DeDRM Plugin when I went to add one of my new ebooks to my Calibre library and discovered the DRM was still attached.

Calibre add a kindle drm removal plugin