With the author Satsuoni's help, the latest DeDRM plugin v10.0.18 for Calibre finally works out. Different from pvevious version of dedrms / no drm fork(v10.0.9), the new released version adds a tool named kfxkeyextractor which is essential for obtaining a cryptographic key from Kindle books downloaded via Kindle for PC version 2.8.0, 2.8.1 and 2.8.2, 2.8.3.
Though it works for the latest version of Kindle PC app, but the how-to steps are not as simple as before.
Unlock KFX Books Without a Kindle Device.
Solution 1. DeDRM V10.0.17 + Kindle for PC V2.8.3
Solution 2. DeDRM V10.0.9 + Kindle for PC V2.4.0
Solution 3. Epubor Ultimate + Kindle for PC V2.8.3 (or Kindle for Mac v7.52)
This process is for personal use only on books you legally own, don't transfer or upload them to any online websites.
My Environment: Win 10 64bit, Calibre v9.3, DeDRM v10.0.18, KFX Input v2.29
Step 1. Download the latest version of Calibre for Windows from the official page.
Step 2. Download the latest version of dedrm plugin v10.0.17 v10.0.18(released on Feb 28, 2026, for ripping the newest amazon key system).
Once finished the downloading, UNZIP it.
Step 3. Download the latest version of KFX Input plugin v2.29.0. The KFX Input plugin is used for converting KFX format (drm protected kfx will be turned into KFX in calibre) books to other formats such as PDF, ePub, AZW3, DOCX, Mobi, ZIP, etc..
Download KFX Input plugin v2.29.0 here
Where can I find the latest DRM removal tools for Calibre? The current fork is NoDRM v10.0.9, officially it won't be updated anymore. As of Februray 2026, the latest version was released by Satsuoni and it works with Kindle PC V2.8.3. You can try to visit the Satsuoni release page to get the latest upates at anytime.
Install the DeDRM_plugin.zip(Optional) and KFX Input.zip to Calibre Separately
(To remove the drm from latest version of Kindle kfx/azw books, there is no need to install the dedrm plugin to calibre anymore, because the kfxarchiver.exe will help crack kfx books to drm free kfx-zip directly without using the dedrm plugins. But considering you may also need to use the calibre to crack your kobo or acsm books, why not get the dedrm plugin prepared in advance? )
Open Calibre, go to Preferences > Plugins, and click "Load plugin from file." Select the downloaded DeDRM_plugin.zip and confirm the installation.
Repeat the same steps to add KFX Input.zip plugin file to Calibre.
Restart Calibre to finalize both plugins installation, otherwise the plugins won't take effect even though you imported your Kindle books to calibre library successfully.
Copy KFXArchiver283.exe into Kindle App File Location (PC V2.8.3/V2.8.2)
Note that the drm plugin v10.0.18(and above) only works for books downloaded via the Kindle for PC V2.8.3, Kindle4PC V2.8.2.
Download Latest Version of Kindle for PC here
After finish the installing of kindle pc app, locate the app file location. Then copy the KFXArchiver283.exe from the DeDRM_tools folder to its root directory (typically is c:\Users\<username>\AppData\Local\Amazon\Kindle\application).
Log in to Kindle Library and Download Kindle Books.
Be logged in and synchronized in the Kindle pc app. Then, double-click on the book cover to download Kindle books for offline backup.
By default, the downloaded Kindle books will be located under "My Kindle Content" folder (typically is c:\Users\<username>\Documents\My Kindle Content).
New kfxoutput Folder and Execute Command Line to Generate the k4i File
Create a new folder and name it kfxoutput under "C:\Users\username\.
This step is esstential. If this folder doesn't exist, you will fail to create the key k4i file.
Get started the Command Prompt(Win+R - execute “cmd”) and run the following utility:
C:\Users\username\AppData\Local\Amazon\Kindle\application\KFXArchiver283.exe "C:\Users\username\Documents\My Kindle Content" "C:\Users\username\kfxoutput" kfxoutput.k4i
Replace (username) with your Windows username. Assuming that (My Kindle Content) is where your books are stored. You can also try to search and locate "My Kindle Content" folder, and then right-click and copy the file path for the "My Kindle Content" folder and then replace the one in the command.
Click Enter. Successful output should show:
Found sought after function by name
Trying to open ***_EBOK
---
DRMION decrypted and saved.
Read file of *** bytes.
"device_serial_number": "***"
Working secret: "***"
Writing DSN and secrets into kfxoutput.k4i
If you just see messages like "Found sought after function by name, got offset" and no "DRMION" tips, click Enter again and again until you see them.
Now the kfxoutput folder and the kfxoutput.k4i file are saved under "C:\Users\username\.
The kfxout folder should contain the decrypted files. They are in kfx-zip format. But after you adding the kfx_input plugin to calibre, these files will be turned into drm free kfx format.
Customize DeDRM Plugin and Copy the k4i file to Calibre (Optional)
(You can skip this step unless you downloaded one book with an old format kfx.)
Go into Calibre/ Preferences/ Plugins, and select "DeDRM plugin v10.0.14". Hit "Customize Plugin".
Click on "Kindle for Mac/PC ebooks" and select "Import Existing Keyfiles" icon to add the kfxoutput.k4i file.
Apply the customization and restart Calibre.
Import kfx-zip file to Calibre Library (convert kfx-zip to kfx, convert kfx to epub/pdf)
Now directly copy kfx-zip files from kfxoutput folder to Calibre library.
If you get a normal "KFX", it means the kindle book's extracting job is finished perfectly. If you get "KFX-ZIP", it means the processing is failed. Try re-extracting your keys and reconfiguring the plugins please.
DON'T drag azw format books from My Kindle Content folder, otherwise you will still get the kfx-zip error.
Continue, click on "Covnert books" and select "ePUB" or "PDF" as output format to convert kfx-zip to epub/pdf .
Extracted Kindle Books Appear as KFX-ZIP Files? A Quick Fix for KFX Error.
When you see "KFX-ZIP"(This Book is Locked by DRM), you should realize that you may have done something wrong during these steps.
- Use the latest version kindle for pc version 2.8.3, 2.8.2 please. Each one will be OK.
- If you added incorrect plugins, you will fail to dedrm.
- If you did not execute the command according to the specified standard command line, you will fail.
- If you get an empty k4i file, you will fail.
- If the kfxoutput folder doesn't exist, the k4i file won't be successfully generated.
- If your Kindle4PC is installed (Kindle Directory) at C:\Program Files (x86)\Amazon\Kindle\, the utility might not work. In this situation, try to use the dedrm plugin v10.0.9 or Epubor Ultimate.
- Note that the kfxarchiver.exe only works for new kindle kfx format books, however, some of Kindle books will use the old KF8 or Mobi format, which causes this package fail to work.
- Every time you download a new book, you need to repeat the procedure to create the k4i file. I mean, Empty all files from kfxoutput folder and delete the k4i file first, then download all books, and last run command line to generate new kfx-zip files and k4i file.
Summary of Calibre 2026 KFX DRM Errors and How to Fix
| Error Type | Common Symptoms / Error Messages | Root Cause | How to Fix |
|---|---|---|---|
| 1. Tool Execution Error | Double-clicking the .exe does nothing; program doesn't open. | The tool is a command-line utility, not a GUI app. | Run it from Command Prompt/Terminal with the correct syntax: KFXKeyExtractor28.exe "path_to_My Kindle Content" kindlekey.txt kindle_account.k4i |
| 2. Version Mismatch & Crashes |
|
Using the wrong tool version for your Kindle app. The new tool is only for Kindle for PC 2.8.0 / 2.8.1 / 2.8.2 / 2.8.3 |
|
| 3. Plugin Configuration Error | Tool runs and creates keyfile, but Calibre still says the book has DRM when converting. | The extracted keyfile is not correctly linked to the DeDRM plugin in Calibre. |
|
| 4. Incomplete Key Extraction |
|
|
|
| 5. Path & Syntax Issues |
|
Incorrect command syntax or path to the My Kindle Content folder. |
|
A detailed step-by-step infographic of the Kindle KFX DRM extraction process:
In my opinion, when you get kfx-zip error, I highly recommend you update the plugins and re-download Kindle books and extract kindle books again (generate the kindekey text file and kindle_account k4i file). As a better alternative, you can also get a free trial of Epubor Ultimate.
There is no need to import and customize the plugins and create essential key files (high risk of failures), and it automatically imports all of the downloaded Kindle books. What's better, whenever you download a new book and you wish to convert it, you only need to sync within epubor ultimate and drag it to the rigt area, no additional steps to customize and recreate new key file. In a word, it is extremely easy and seamless to link, download and extract Kindle to PDF ePub files with literally a few clicks, so that you can access them whenever you need to.
Customer Story: I Prefer to Use Epubor Rather than Calibre Plugins
I followed the many instruction sets that appear on Google, Reddit and other sources. I got the KFX Input plugin for Calibre. I got the DeDRM plugin. I got the KFXKeyExtractor and used it to get my Kindle key and setup the DeDRM plugin. I spent a solid hour trying different configuration tricks. I got Calibre to properly import the books, but I could not get it to decrypt and convert them.
Epubor Ultimate was much more straightforward. I loaded the books, I added them to the decrypt list, and then I converted them to PDF issues without any problems.
Angel Dan has covered software online marketing for more than 10 years. She joined Epubor since 2013, covering content writing, affiliate marketing, global brand expansion, video marketing, and business development.
Hi, I received an error message when I try to run the extractor key : Qt: Untested Windows version 10.0 detected!
Got offset: 2829bf0
I run Windows 11 pro (in french) so I don't understand why the message speaks about Windows 10... and why it doesn't work. Thank you for your help and sorry for my bad english.
Joëlle
Angeljo
Any mroe problems, please feel free to contact me at epubor.service@gmail.com.
Just a little note: on my PC the 2 key files were generated in C:\Windows\SysWOW64
Great work!
i get this error...(Windows11, Calibre v8.12, DeDRM v10.0.15, KFX Input v2.27)
Found sought after function
Got offset: 29e0000
QObject::startTimer: Timers can only be used with threads started with QThread
DSN 7d7GnJ6nr15bn0nbP7PP6M71t3t576P8tkrJrkn0
Tokens bs4zgmEFYz4dbAgq1/nQVP/Z2k1ADJb+GfDPzTkh/irN3CmADA4cx4BmYnJHR80/8Ow93LjteN3+3dmQ+tMosw==
Fontconfig error: Cannot load default config file
Could not open directory
any advice? thanks in advance!
Please uninstall the DeDRM plugin and run the command again. If it fails, please verify that you have selected the correct directories for both the kindlekeyextractor.exe file and your Kindle content folder.
For a much simpler user experience, we recommend trying Epubor Ultimate.
Você poderia me ajudar com esse problema:
Toda as vezes que eu digito (C:\Users\Gabriel Pereira\AppData\Local\Amazon\Kindle\application\KFXKeyExtractor28.exe "C:\Users\Gabriel Pereira\Documents\My Kindle Content" kindlekey.txt kindle_account.k4i) dá erro.
A mensagem que parece é
'C:\Users\Gabriel' não é reconhecido como um comando interno ou externo, um programa operável ou um arquivo em lotes.
Ficarei muito grato pela ajuda.
Até mais.
I am stuck at the run command lines step. No matter what I do i keep getting an error: C:\Windows\System32>C:\Users\CourtneyGoodman\AppData\Local\Amazon\Kindle\application\KFXKeyExtractor28.exe "C:\Users\CourtneyGoodman\Documents\My Kindle Content" kindlekey.txt kindle_account.k4i
The system cannot find the path specified.
What am i doing wrong?
Thank you for documenting this method. I stayed up way too late but finally have a readable ePub today.
In case it helps anyone, I had to right-click and copy the file path for the "My Kindle Content" folder and then replace the one in the command, since the true path was under OneDrive.
Figured out the issue if you are missing your .k4i and kindlekey.txt files and cannot find them after the script runs. At the end of the command, where she outputs the file names, it will not save them on some systems (even if you run the cmd prompt as admin) if there are certain folder permission or drive encryption set up. So I modified the end of the script to add the whole file path before the filenames and it works:
changed this...
C:\>C:\Users\username\AppData\Local\Amazon\Kindle\application\KFXKeyExtractor28.exe "C:\Users\username\Documents\My Kindle Content" kindlekey.txt kindle_account.k4i
to this...
C:\>C:\Users\username\AppData\Local\Amazon\Kindle\application\KFXKeyExtractor28.exe "C:\Users\username\Documents\My Kindle Content" c:\users\username\kindlekey.txt c:\users\username\kindle_account.k4i
And I got my files!
Just answered my own question, I think...
I uninstalled Calibre v9.x, re-installed v8.16.2 and re-installed the plugins, and voila--worked right away again. Oops.
There isn't a kindle for pc version 2.8.2;. The latest version as of today is 2.8.0.70980; that is the version the link you provided downloads automatically and the version you get when you download directly from amazon.
Requesting an update on the info provided above as it is confusing.
I'm nervous now to even try to install anything because I am uncertain if this will work as when I attempted to update a day earlier using the upgraded/latest calibre and kfx input (the same one you provide here today), but with dedrm 10.0.15 as was on here a day ago, it did not work; now I see there's an upgraded version to the dedrm; perhaps that was why it didn't work yesterday(?)
Since there isn't a kindle for pc v2.8.2 but I do have the latest version downloaded; will this work now with the latest kfx_input 2.29.0 and dedrm 10.0.17?
I will try it but am skeptical only because the ones you had listed yesterday didn't work.
Thankful for a reply to my inquiry.
Enjoy a wondderful dau and... Thank you
Yeah. O just moved through all the newest steps you've provided and it does NOT work. NO kfxoutput file is is showing up in my user folder at all.
Very frustrating. This worked before with dedrm 10.0.14 but ever since the upgrades to that and the kfxinput... NOTHING. None of the text files or the current outputput files are showing up.
Do you have the link for the dedrm 10.0.14 and all the other original files links? because the new steps are not working and I just reset my pc to factory in hopes just this program to de-drm my kindle books would finally work. I went and reset everything ONLY for the purpose of getting THIS one thing to work!
FRUSTRATED
Okay, finally got it working. I
had to hack it a bit with some pointers from others through comments, the 2nd time around when the first time failed after a pc factory reset and following the above instructions proved useless; but in case anyone else is struggling with getting this to work like I did, here’s how I fixed
Firstly, the link for kindle for pc you have here takes you to version 2.8.70980, that much is the case. I installed it because there was/is no 2.8.2 that downloads from amazon.
I followed all the steps, downloading the updated versions of Calibre, DeDrm and KFX_Input, via the links provided above. First, I installed KFX_Output plugin from within the calibre app, restarted then proceeded to follow the rest of the steps for adding both the DeDRM and KFX_Input plugins.
Next, I installed Kindle for PC version 2.8.70980 (as that was/is the only version to download both via the link provided above or through amazon). After installing, I closed it.
The next thing I did was go to the kindle for pc install directory as per the instructions above, but instead of only copying the KFXArchiver282 file, I also copied and pasted the KFXKeyExtractor28 (as per the original instructions a day ago.
I then went to sign into kindle for pc by launching it again. THAT IS WHEN YOU SHOULD BE PRESENTED WITH THE VERSION 2.8.2 to which I was. I updated it, close the app again, relaunched it, signed in, then downloaded all the books I wanted converted.
I created the folder “kfxoutput” then proceeded with the “cmd” prompts as given above
When I attempted to use the code (with my username), it again failed again. No file named “kfxoutput.k4i” ever appeared in my username folder and all the books in the kfxoutput folder were all zipped (again); so, I tried a different tactic.
Dirst, I deleted all the zipped files inside the kfxoutput folder then borrowing a suggestion from another commentor where a certain line of code worked for them; I put in the following prompt in the CMD console; foregoing any reliance on the kfxoutput code (my pc username is removed for privacy):
C:\Users\username\AppData\Local\Amazon\Kindle\application\KFXKeyExtractor28.exe "C:\Users\ username\Documents\My Kindle Content" c:\users\ username\kindlekey.txt c:\users\ username\kindle_account.k4i
GUESS WHAT HAPPENED… IT WORKED. Both the “kindle_account.k4i” and the “kindlekey” text files appeared in my username folder as it should have done using the old instructions that are now gone from this page above and gas been replaced with the kfxoutput code.
I then proceeded to customize the DeDRM plugin in the calibre app; imported the “kindle_account.k4i” (now showing up in my user/isername folder and added the text file, clicked apply then closed and reopened calibre (no “restart” option like with the other plugin add options); from there, I proceeded to import my kindle books, clicked on convert and everything worked; FINALLY.
Angel Dan does an amazing job and I have no intention of taking anything away from her and all her hard work, however, for me, the most recent edits are lacking. The new way does not work at all so, I hope this helps those finding themselves stuck and frustrated over the new steps not working and that the steps I took could help them out, at least for now.
Thanks Angel Dan for letting me post this. Blessings
Dear Lori K,
I updated this article after I got the updates from Github about the dedrm plugins, and then I tried it by myself and I decided to update this post, too.
It works for me, and also I skip the kindle for pc v2.8.2 updates and keep using the Kindle for pc v2.8.0, and then do the following steps, I finally succeeded too.
The dedrm plugin v10.0.17 must work with:
Calibre v9;
KFX Input plugin v2.29
Kindle for PC V2.8.2 or v2.8.1 or 2.8.0
Of course, if you keep using the 2.8.0, you can also try to use the previous method or steps, as what I have introduced in this video.
youtu.be/gmbtUCnewn8
Estimado, este es mi error, solo me pasa con algunos libros con varios me ha funcionado, saben que podra pasar o es una nueva encriptacion
sl2
Found Kindle executable of version Kindle 2.8.0(70980)
Got offset: 21a0000
QObject::startTimer: Timers can only be used with threads started with QThread
DSN 5k54tEPz6d7zSzPzSdnAP4Sv5krfSCPCP552nb7n
Tokens nwyoNhkUrB1WfC9T/BcZoXdjCfySXfn1UwO4Sec++AULESmHBqQHUEb8un6pfO0G8AFywpjKcLaLhzfHtLePSA==
Fontconfig error: Cannot load default config file
Trying to open B0995PRVVS_EBOK
BookOpen error 14 Missing magic bytes
Invalid book format, maybe KF8/MOBI?
Trying to open B09SXHKHXL_EBOK
BookOpen error 14 Missing magic bytes
Invalid book format, maybe KF8/MOBI?
Trying to open borrar
Writing DSN and secrets into c:\Users\Juan\kindle_account.k4i
Import the kindle_account.k4i to Calibre DeDRM plugin first, and then drag your kf8/mobi book files from "my kindle content" folder to calibre library.
estimados, muchas gracias por responder he segiuido todos sus paso, incluso los últimpos del mesnaje de respuesta
Intentando abrir B09SXHKHXL_EBOK
. Error 14 al abrir el libro. Faltan bytes mágicos.
Formato de libro no válido, ¿quizás KF8/MOBI?
Intentando abrir. Borrar.
Escribiendo DSN y secretos en c:\Users\Juan\kindle_account.k4i.
para que entiendan que este libro no lo logra abrir y desbluear de hecho lo que me arroja elñ pdf son imagenes y no los textos, espero haberme explicado bien, saludos y gran contribucion