KFX Converter, Convert KFX to PDF/EPUB/Mobi on Win/Mac (Catalina & Big Sur Included)

Jacinto Wilson
5 min readAug 27, 2020


More and more Kindle books are KFX books nowadays. No matter the books downloaded via Kindle for PC/Mac or Kindle e-ink devices, they are all in Kindle KFX format. To read Kindle books more freely, sometimes we may need to convert KFX to PDF, ePub, Mobi or TXT.

Method 1. Downgrade Kindle for PC/Mac to Older Version

Step 1. Download Kindle for PC/Mac desktop app to your computer.

Download Kindle for PC 1.24 here.

Download Kindle for Mac 1.23 here.

NOTE: (1) If you have already installed the latest version of the Kindle desktop app, please first unistall it and then install the older version. Please note that Kindle for Mac V1.23 cannot be installed on macOS 10.15 Catalina and macOS Big Sur, because Kindle for Mac V1.23 is 32 bits while macOS 10.15 or higher only supports 64 bits applictations. (If you want to convert KFX books on mac Catalina or higher, you can take Method 2.)

(2)Please stop the Kindle for PC/Mac automatic update manually. Open Kindle desktop app>Click “Tools”>Options>General>uncheck the “Automatically install updates when they are available without asking me”>Save.

Step 2. Download Kindle books via Kindle for PC/Mac

Run Kindle for PC/Mac and sign in with your Amazon account. You will find all your purchased Kindle books in the library. Just double-click the book cover to download the books to your computer.

After the download has been finished, the Kindle eBooks you downloaded are not with the extension .kfx, but .azw, which exactly are KFX books but with .azw extension. The downloaded kindle books are usually saved in the folder of “My Kindle Content”

Step 3. Convert KFX to PDF/EPUB/Mobi/TXT with a KFX Converter.

There are not many KFX Converters in the world. Ultimate Converter is the easiest-to-use and most user-friendly one I’ve found.

Run Ultimate Converter. The books you have downloaded via Kindle for PC/Mac will be automatically detected by this software under the Kindle tab at the left column. Now just drag the books from left to the right main window, and then we need click the blue “Convert” button at the bottom to convert Kindle KFX to PDF/EPUB/Mobi/TXT.

In a second, the conversion is completed. You will see a “Succeeded” under each book title. And you can click the “Succeeded” word to find the converted Kindle books in PDF/EPUB/Mobi/TXT format.

Method 2. Disable KFX Support in Kindle for PC/Mac

To take this method, you don’t need to downgrade to use the older version. Just keep your Kindle for PC/Mac desktop application as the latest version.

Step 1. Delete all your Kindle books from your Kindle library.

Run your Kindle for PC/Mac, click “Downloaded” at the left menu, then right-click the book cover, and choose “Remove From Device”.

(If you haven’t downloaded any Kindle books via the latest version, just ignore this step.)

Step 2. Exit Kindle for PC/Mac.

Step 3. Disable KFX support in Kindle for PC/Mac

In this step, the process on Windows is a bit different from that on Mac. Please pick up the one that is consistent with your computer system.

For Windows users:

Download KFX_begone3.zip to your PC. Unzip the file, you will get the Kindle.cmd file. The cmd file is a command. Now open the cmd file to run the command line.

When you run the command, your Kindle for PC will be automatically opened. You don’t need to do anything further. Just wait for the command to be finished.

For Mac users:

Open the terminal window, and cut and paste the following command to disable the renderer-test program.

chmod -x /Applications/Kindle.app/Contents/MacOS/renderer-test

If you fail to convert the files even though you have run the command, please add “sudo” before the above command to ensure 100% success.

sudo chmod -x /Applications/Kindle.app/Contents/MacOS/renderer-test

Put the above code in the Terminal and then tap “Enter” on your keyboard, you will be requested to fill in your computer passwords. Just fill in it and tap “Enter” again. That’s it. Just take the next step.

Step 4. Run Kindle for PC/Mac V1.30, re-download Kindle books to your computer by “right-click” and choose “Download”.

Note: Don’t double-click the book to download it. And don’t open the book until you convert the book successfully. Otherwise, you will fail.

Step 5. Download and run latest version Ultimate Converter (V3.0.12.1028 or higher).

You can just drag the books from the “Kindle” tab at the left column to the right main window and click the bottom blue button convert the ebook formats to PDF, ePub, Mobi, AZW3, TXT.