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Exactly How to DeDRM with Calibre (plus 10 effective solutions if failed)

December 6, 2020 terminator 0 Comments

When talking about Calibre DRM Removal 2020, we will know that we should add DeDRM tools to Calibre because they are must-have if we want to remove DRM from eBooks with Calibre.

In this post, I’ll focus on DeDRM with Calibre for Kindle/Kobo/ACSM eBooks part by part — and 10+ exclusive and effective solutions if you meet errors.


1. DeDRM from eBooks is acceptable only when you want to backup or share your own files. DON’T resell those drm free eBooks and respect every author please.

2. This post introduces exactly how to dedrm eBooks from Kindle, Kobo and Adobe Digital Editions (such as Google Play books) files. Apple books and Nook ePubs are not supported now.

3. DeDRM tools only work on our own purchased eBooks, eTextbooks and rented eBooks are not supported.

4. Here what I introduced are all tested on my personal Windows laptop and Mac computer. Calibre supports Linux, if you meet any problems when running calibre drm plugins on Linux, please contact Alf team to ask for help as I didn’t test Calibre DRM Removal for eBooks on Linux.

Part 1. Preparing (What You Need)

  • 1. Calibre 5 and noDRM plugin v10.0.0 (Or dedrm v6.8.1 for calibre 4)
  • 2. Kindle/Kobo/Adobe eBooks downloaded via official desktop app.
  • 3. Import eBooks to Calibre to DeDRM or unlock eBooks.

Latest update 2022:

1. The Apprentice Alf blog stopped maintaining the DeDRM tools in 2021, and now noDRM is taking over maintaining the project. It contains 2 plugins for calibre, DeDRM and Obok.
2. The v10.0.0 versions of this plugin should both work with Calibre 5.x (Python 3) as well as Calibre 4.x and lower (Python 2). 
3. Users with calibre 5.x or later can use the latest version of plugins now. Users with calibe 4.x or earlier should use release 6.8.x of the tools.

Part 2. How to Add DeDRM tools to Calibre?

This is how you add a plugin to the Calibre program.

(Latest update: You can also download the latest dedrm tools v10.0.0 and calibre 5.)

Step1. Download Calibre version 4.x or earlier.

Step2. Download DeDRM_tools_6.8.1.zip and unzip it.

unzip dedrm tools calibre

Step3. Add downloaded plugin zip file to Calibre.

Run calibre, select “Preferences” > “Plugin” > “Load plugin from file”, then choose the “DeDRM_plugin.zip” or “Obok_plugin.zip” from the unzipped DeDRM_tools_6.8.1 archive, click on the “Open” button. Ignore the “Are you sure?” warning dialog(Yes”), then A “Success” dialog will appear, saying that the plug-in has been installed. Click on “OK” and then “Apply”.

load plugin from calibre file

Step4. Restart Cablire.

Part 3. DRM removal plugin failed to install Issues

Have followed the above steps but the calibre dedrm plugin is not working?

SyntaxeError: invalid syntax

calibre, version 5.1.0
ERRORE: Eccezione non gestita: <b>SyntaxError</b>:invalid syntax (calibre_plugins.dedrm.__init__, line 168)
calibre 5.1 [64bit] embedded-python: True is64bit: True
Windows-10-10.0.19041-SP0 Windows ('64bit', 'WindowsPE')
('Windows', '10', '10.0.19041')
Python 3.8.5
Windows: ('10', '10.0.19041', 'SP0', 'Multiprocessor Free')
Interface language: it
Successfully initialized third party plugins:
Traceback (most recent call last):
  File "site-packages\calibre\gui2\preferences\plugins.py", line 317, in add_plugin
  File "site-packages\calibre\customize\ui.py", line 472, in add_plugin
  File "site-packages\calibre\customize\ui.py", line 61, in load_plugin
  File "site-packages\calibre\customize\zipplugin.py", line 200, in load
  File "site-packages\polyglot\builtins.py", line 123, in reload
  File "importlib\__init__.py", line 169, in reload
  File "<frozen importlib._bootstrap>", line 602, in _exec
  File "site-packages\calibre\customize\zipplugin.py", line 179, in load_module
  File "calibre_plugins.dedrm.__init__", line 168
    print u"{0} v{1}: Copying needed library files from plugin's zip".format(PLUGIN_NAME, PLUGIN_VERSION)
SyntaxError: invalid syntax
invalid syntax error

As of calibre 5, calibre has moved from Python 2 to Python 3, because Python 2 has been end-of-lifed.

To resolve this bug, you just need to update your Calibre to the latest version, and then add the DeDRM plugin v7.1.0 to calibre. If you’ve added the older version of drm plugins, delete it from calibre first and then re-import.

Unhandled exception: does not contain a top-level init.py file

calibre, version 4.23.0
ERROR: Unhandled exception: InvalidPlugin:The plugin in u'/Users/bradcrandell/Downloads/DeDRM_tools_6.8.0.zip' is invalid. It does not contain a top-level init.py file
Python 2.7.16
OSX: ('10.15.3', ('', '', ''), 'x86_64')
Interface language: None
Successfully initialized third party plugins: Gather KFX-ZIP (from KFX Input) (1, 9, 0) && Package KFX (from KFX Input) (1, 36, 0) && KFX metadata reader (from KFX Input) (1, 36, 0) && KFX Input (1, 36, 0) && Set KFX metadata (from KFX Output) (1, 23, 0) && KFX Output (1, 23, 0)
Traceback (most recent call last):
File "site-packages/calibre/gui2/preferences/plugins.py", line 319, in add_plugin
File "site-packages/calibre/customize/ui.py", line 472, in add_plugin
File "site-packages/calibre/customize/ui.py", line 61, in load_plugin
File "site-packages/calibre/customize/zipplugin.py", line 194, in load
File "site-packages/calibre/customize/zipplugin.py", line 292, in _locate_code
InvalidPlugin: The plugin in u'/Users/bradcrandell/Downloads/DeDRM_tools_6.8.0.zip' is invalid. It does not contain a top-level init.py file
calibre invalid plugin

You see this error may be because you added the whole archive file into calibre. Unzip the DeDRM_tools_6.8.1 archive, and look in the DeDRM_tools_6.8.1 folder for the zip file(named DeDRM_Plugin.zip and Obok_plugin.zip) to load into calibre.

Another reason is the downloaded drm plugin file is not the latest version. If so, you should remove the older version plugin first, and then download the latest one and import them again to calibre.

Part 4. How to unlock DRM from Kindle KFX eBooks with Calibre plugin?

Since Amazon started using new KFX format to Kindle eBooks, calibre plugin no longer works for unlocking DRM from KFX format. The DeDRM plugin here works with non-KFX Amazon books only, and the solutions introduced here are walkaround solutions, not the direct (quick) one.

Note that Amazon changes the DRM for KFX files frequently. What works for KFX today might not work tomorrow.

1. The plugin doesn’t work on books downloaded from Kindle Fire(HD) tablets, Kindle for Android/IOS applications.
2. The tools do not work with the Windows 8 AppStore Kindle app.
3. To convert KFX to ePub/PDF with Calibre, the KFX Input Plugin (version 1.36.0 at the time of writing) must be installed too.
4. If you have a Kindle e-ink device, don’t directly download and import books to calibre as it doesn’t work on these files. But you can download and transfer via USB to your device, then the downloaded file will be .azw3 format. Import azw3 to Calibre and configure the DeDRM plugin by inputting KSN, then you can also remove drm.
configure ksn

Walkaround 1. (For Windows) Install an outdated Kindle (such as version 1.17)

If you have downloaded the latest Kindle for PC, deregister the Kindle PC app first, and then uninstall it from your windows computer.

kindle desktop deregister

Install, launch, and register this Kindle installation with your own amazon account.

Don’t forget to uncheck the auto-update from Kindle’s settings. Otherwise, when you launch it next time, it will update to the latest version automatically, which does not work with DeDRM.

disable auto-update for kindle

If asked if you want to update to the newest version, always select “Skip this version” please.

Now you can select books from your Kindle library and download them to your local Windows.

double click to download kindle


You can find(and even change) the kindle for pc books location by clicking on “Tools” > “Options” > “Content” > “Change Folder”.

Import Kindle books to Calibre library, and the DRM will be removed.

dedrm kfx calibre

As the above image shows, the drm removed KFX books will be turned to KFX(non-DRM). After you installed the kfx input plugin to calibre, you can continue to convert kfx eBooks to other formats.

Walkaround 2. (For Mac) Avoid KFX downloads by renaming renderer-test on Kindle for Mac


For mac computer users, we can also use an older version kindle for mac(such as v1.17) to get around the new kfx format. But in fact, considering that the older version kindle app can’t run on catalina and big sur, while more users have updated (or will update soon) their mac system to the newest one, so here I write down this solution in detail for Mac users, save your time to understand and test.

The key to avoiding KFX downloading from K4Mac 1.25+ is to block KFX with chmod -x, then download books using right-click on mouse and selecting “Download”.

Install the latest version of Kindle for Mac or update to the latest one, v1.30.

latest kindle for mac

If there are kindle books already in the “Downloaded” tab, remove them first(Remove from device).

Then, run Terminal app, copy and paste following command in terminal, if needed input password to execute command.

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

If you don’t have a password, then run this command.

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

After patching the Kindle app, run the Kindle app and select one book, right-click and “Download”.

The downloaded books are saved under “My Kindle Content” folder. By clicking Kindle > Preferences > Content > Change Folder, you can find and modify the location.

Now you can import the downloaded kindle books from “My Kindle Content” folder to Calibre, then as what you see, the drm is removed automatically and calibre turns these books to AZW3 format.


Right-click to download is key important. If you double click to download the book, you will get the new kfx or kcr format.
After the downloading is completed, DON’T double click to open it, otherwise it will cause the Kindle app crashes unexpectedly. The downloaded old format is incompatible with the newest kindle app. After all, amazon prefers us to download and use the new KFX format.

Kindle KFX DeDRM Failed and Solutions

01. The Kindle DRM has been removed, but all the pictures are gone

Most likely, this is an AZW6 format book that the tools don’t support. But as the azw6 is only downloaded directly via Kindle e-Ink device, so the solution is downloading your book by “Download & Transfer via USB”.

02. The Kindle book (AZW4) conversions takes a long time

The AZW4 is a Print Replica Kindle ebook. This is a PDF in a Kindle wrapper. After you adding it to Calibre, the azw4 DRM will be removed successfully. Now all you should do is using the KindleUnpack plugin.

03. AZW/KCR/KFX-ZIP in Calibre

In fact, if Calibre shows the book in “AZW”, “KCR”, “KFX-ZIP” format after you add one book to the calibre library, it’s likely that Calibre failed to remove its DRM.

See, after I click on “Convert books” and select “epub” to convert, calibre shows the above error message.

To avoid this, I would say please follow all the details step by step as what I write at the above.

You can also click on the “Jobs: 0” label in the lower right corner of the calibre window to activate the Jobs dialog.

show calibre job details

Select the failed conversion job from the list (the most recent will be first) and click the “Show job details” button. Copy the log to the clipboard and then paste it to Github or Mobileread for help.

DRM plugin driving me mad? If you think Calibre and the plugin are complex, here you can choose a good alternative, iSummersoft Kindle Converter.

kfx dedrm failed solution isummer

When started, it will detect your computer system and show you the official guide on how to download your kindle books in the correct way. And then, after you downloaded books well, it will auto-detect your books and show them at the left side. All you need to do is just to add them from the left to the right area, choose output format (from ePub, pdf, mobi, azw3, txt, docx options) and convert.

Part 5. How to disable DRM from Adobe Digital Editions (ACSM)?

The installed DeDRM plugin also works on Adobe ACSM files, such as the downloaded books from Google Play.

downloaded acsm

You will find that the downloaded file is in acsm format. ACSM is associated with Adobe Digital Editions. It means we must use the ADE to open this type of files.

authorize computer with adobe id

The first time running ADE, you should authorize an Adobe ID, and then open your acsm with it. When the acsm is opened via ADE, the acsm is turned to ePub or PDF (depends on ebooks vendors), but with DRM. And they are stored under “My Digital Editions” folder.

adobe drm removal calibre

Now you can import them from the digital editions folder to Calibre. Then, the Adobe DRM is removed by the dedrm plugin in Calibre.


Not all the acsm files that you downloaded from an online eBook store will be supported by the dedrm plugin, though you can open them via ADE.

You may meet problems when authorizing an Adobe ID or opening acsm file via ADE.

Please ensure that you are using the same email address as your ebookstore account’s, this is important. Another reason is you used an incorrect Adobe ID, if so you should switch your adobe account to login.

A Complete Guide on How to Convert Adobe Digital Editions(ACSM) to PDF

What is an ACSM file? Why should we use ADE to open this type of file? Is it possible to convert and print adobe to normal PDF?

Part 6. How to Use Calibre kepub plugin?

The Obok_plugin.zip you added to Calibre is used for removing DRM from Kobobooks. By default, Calibre will show this plugin at the top menu bar.

Firstly, you should use Kobo for PC/Mac to help download your books.

Where to find them? Books downloaded via Kobo PC are saved here:

…\AppData\Local\Kobo\Kobo Desktop Edition\kepub

And Kobo for Mac books are saved in this location:

.../Library/Application Support/Kobo/Kobo Desktop Edition/kepub

Launch Calibre and click on the “Obok” plugin. If you don’t see it, click on the three dots icon at the top menu bar.

Then from the popup window you will find that it automatically detects all of your downloaded Kobo EPUB books.

The red lock icon means that book is drm protected, and the green lock icon means that book is drm free. To crack those drm protected books, you can click “All with DRM” and then touch “OK”. Wait for the job to complete.

convert kobo to epub calibre

Now the drm limitation is removed from your Kobo books, and they are in EPUB format (the original is kepub, with drm). If you want to transfer Kobo books to Kindle, you can continue to convert them to Mobi format in Calibre.

Tips that work:

1. If you already downloaded Kobo books on Kobo eReader, you can also connect it to the computer and then import that book to calibre so that you can remove DRM directly from them.

2. If you use the Kobo desktop app to help download files, download and install the app from Kobo official site please. DON’T install the app from any app stores. Otherwise, you may fail to remove DRM from kepub.

3. Couldn’t find the kepub folder on Mac? Use Terminal and running following command: write com.apple.finder AppleShowAllFiles yes
then Enter.

Final Words, with Some Useful Tricks

This is all I could share with you on Calibre DeDRM 101. If you follow this guide step by step, I think you will succeed in unlocking your purchased eBook files.

  • Check you are using the correct version of Calibre.
  • Check you are using the latest version of Plugins.
  • Downloading eBooks via desktop app makes the DeDRM more easier to function.
  • Re-import eBooks to Calibre again.
  • The drm is removed after importing the book, not converting it.
  • Don’t forget to submit your error log to Mobileread, github, reddit to get help.
  • Or use the best alternatives from iSummersoft, these products deserve your trial and are much easy to use.
eBooks Type Calibre Plugins Alternative(without Plugins)
Kindle (KFX, AZW, AZW3) DeDRM + KFX Input Kindle Converter
Adobe (ACSM, EPUB, PDF) DeDRM ACSM Converter
Kobo (KEPUB) Obok Kobo Converter
Nook (ePub) / Nook Converter
Apple (ePub) / /

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