How to Add a Kindle DRM-Removal Plugin to calibre

How to Add a Kindle DRM-Removal Plugin to calibre calibre DRM Kindle Tips and Tricks Update: These instructions were updated on  11 July 2015. They worked for me on that day.

DRM is the bugaboo of ebooks.  It's the cause of more pain and agony than a Snooki photo, and today I plan to help fix that. I have long been on the side of removing DRM (it's the best way to protect your purchases), but up until today I had never gone beyond pointing my readers at tools.


The process is minimally difficult and I'd like to share it with you. But first, a few warnings.


  • Note that these instructions are Windows only, and some details will be different between the various versions of Windows.
  • Note that these instructions were written without the permission or participation of Kovid Goyal, the creator of calibre.
  • These instructions are written in order to assist the average user in protecting their purchases. I did not write it to assist in committing piracy; I believe in buying content, when possible. But I also believe in controlling the content I buy and that is why I strip the DRM.


Here's the short-short version: You need to get the DeDRM plugin from Apprentice Alf and install it in calibre (and reboot calibre). Once you've installed the plugin, all you have to do is find where Kindle4PC put the ebooks on your computer and drag each ebook into calibre (everything else is automatic).

Luckily for you, you only have to go through the set up process once in order to remove Kindle, Nook, and Adobe DE DRM. (Kobo is a separate process.) If you've followed my instructions for removing Nook DRM then you've already finished the process of setting up to strip Kindle DRM, and you can skip to the end of this post.

First Things First

You need to download and install these apps on your computer. If you have either of them then you do not need to install them again:

Calibre is of course the ebook library management tool. I've mentioned it once or twice, and that's what you're going to use to remove the DRM.  And K4PC is how you'll download the ebooks.

Install the apps one at a time (and set up your account with the K4PC app, if you haven't already). While it's being installed, go to the Apprentice Alf website and download the ZIP file full of plugins.

Got everything installed? Good.

  1. UnZip the ZIP file you just downloaded. Open the folder called calibre and you should see a folder full of plugins.
  2. Launch calibre. When it's open, look at the icons on the top row. There's one on the far right called "Preferences". Click on it.
  3. It will bring up a new window with a bunch of icons.  Look on the bottom row for the one that says "plugins". Click it.
  4. And now you'll get another new window. Look at the buttons on the bottom row. Click on the one that says "load plugin from file".
  5. Use the file browser window to find the folder you downloaded. Open it, and then open the DeDRM_calibre_plugin folder.
  6. There should only be a single ZIP file in that folder, and it should be called "DeDRM_plugin". Double click to select it.
  7. Shut down calibre and launch it again. Some times the plugin won't kick in until you after you do this.


You've just installed and configured the plugin (assuming all went well).  You should be able to copy any ebook you've downloaded from the K4PC app to calibre.  Calibre should now be able to read the ebooks and convert them to whatever format you prefer.

But before you can do that you'll need to find out where the Kindle ebooks are stored. This varies depending on which version of Windows you're running, but they can usually be found under the My Documents folder.

I'm looking at my Win 7 laptop right now and the  Kindle ebooks are found in "My Kindle Content" under My Documents.

The ones you will need to copy are:

  • MOBI
  • PRC
  • TPZ

After you copy the files into calibre, you might have some trouble getting calibre to open them so you can read them.   Windows will need to be told that calibre can open the files. This should only happen once, so it's a relatively minor issue.

Note that if you simply convert the ebooks to Epub, you won't have this issue.

images by pellestenRosino

Nate Hoffelder

View posts by Nate Hoffelder
Nate Hoffelder is the founder and editor of The Digital Reader: He's here to chew bubble gum and fix broken websites, and he is all out of bubble gum. He has been blogging about indie authors since 2010 while learning new tech skills at the drop of a hat. He fixes author sites, and shares what he learns on The Digital Reader's blog. In his spare time, he fosters dogs for A Forever Home, a local rescue group.


  1. Oblique7 August, 2012

    I was having problems as described above. One thing I didn’t do was REMOVE the books I was trying to convert from the Calibre library. Once you do that and RE IMPORT them – BINGO! it works. Just thought I’d share this tip along with the good advice from others 🙂


    1. ericjt20 January, 2013

      This does work. When I checked the output folder I also saw that the .azw file I imported, named by amazon “B008Q7HR90_EBOK.azw” had been renamed by Calibr to a .mobi file with the book title as the file name. The first time I tried it, it had left it as an .azw file.

      By the way, I converted this book so I could print some pages of it for myself, as it’s a software manual and I prefer not to have to change windows to read instructions. I think it’s fine to remove drm for this purpose or to put it in your own devices. I paid for my personal use of the file, not just one copy of the file. I won’t be sharing it with others, so I feel that is not a violation of copyright or the intent of drm. “Books” are portable in any form, and today’s books are more and more digital. I can’t read this book on my phone, and I don’t have a tablet. I shouldn’t have to buy one to take the ebooks I buy someplace away from my pc screen to read them. And I may buy a larger screen device eventually. Not worried, no guilt. Piracy is where you distribute copies to others, depriving the author income from new user/reader sales. If it’s just you, it’s not theft. I don’t care if the ebook world is defined by devices. I define ebook ownership as person by person, not device by device.

  2. Strauzz13 August, 2012

    I have no trouble with azw3 files, but I got a simple azw file yesterday that calibri wont convert. Any ideas?

    1. DeDRMer13 August, 2012

      Something funny is going on, but I’m not sure if it is with Amazon or changes in Calibre are breaking the process.

      I converted two books today, one book purchased this morning in the AZW3 format on one Amazon account came off without a hitch using the process above. The Calibre software is 0.8.63, Amazon K4PC v1.10.1, and the conversion was to epub.

      A short time later, I purchased another book on another PC, into a different account and had lots of trouble. The Calibre software is 0.8.64, Amazon K4PC is v1.10.1, the Amazon file type was AZW, and the conversion was to epub. Nothing but failure after failure.

      I loaded the plugin a couple of times, I exited Calibre a couple of times, and did all the things suggested with no luck. I then tried to convert to .mobi vs. .epub and again met with failure (i.e., the DRM warning dialog indicating you’re SOL).

      Not giving up, I then deleted all the other books in the Calibre library (careful – Calibre has a nasty habit of really DELETING all your books), exited the program, and when I opened it again and tried to add the single book I wanted to convert, it said it was in .mobi format. Huh? It said it failed, so what’s up with that? I tried the book, it works fine in .mobi. I then tried the conversion from .mobi to .epub and it took about twice as long as usual, but it did work. It took so long (stuck on 67%) that I tried to cancel it thinking it has crashed.

      I hope this helps you, or someone else having trouble because something has changed somewhere, but it does still seem possible.

      I also want to thank Nate for this site and the fantastic information . It’s a small victory to actually be able to use what we paid for without draconian limitations forced upon us, but it’s still a victory.

      I’m not a real ebook fan is this is exactly why; those DRM people are the real pirates IMO..

  3. graveworm22 August, 2012

    Thanks! This worked for me!

  4. Ly22 August, 2012

    Thanks Nate for the clear and straightforward information.
    It worked very well for me : Win7 32bit / K4PC 1.10.1

    I would have never bought ebooks if I hadn’t landed on sites explaining how to remove DRMs. Cheers !

  5. Kam Singh22 August, 2012

    Nate………thank you so much this article helped me out big time!
    All the best to you.

  6. Lane25 August, 2012

    It didn’t work at first, so I deleted the azw from Calibre then added it back.
    Then I converted it to mobi before converting to epub, and it worked.
    Thanks much!

  7. Jeff27 August, 2012

    I have a .azw4 file that I downloaded today from amazon. It is one of those textbook files. I want to read it on my tablet but I couldn’t send it to it so I am trying to dedrm it, but it always fails when parsing, after it tries to convert it to html. I have redownloaded and reinstalled the patch and even tried renaming it to .azw and still nothing. it won’t get past 1%!!!

    1. Nate Hoffelder27 August, 2012

      Is it one of the Kindle Print Ready files? If so then you have a PDF inside the ebook.

      I would import the ebook and then tell calibre to save it to an external folder. That should be enough to remove the DRM.

  8. Jeff27 August, 2012

    Yes it is nate. It is simply an all in one .azw4 file that is 133mb in size. I also did try to save to an external folder and reinsert into calibre to change it to mobi to read on my tablet, but this is no help. Once I export it then the drm is gone?

  9. Jeff27 August, 2012

    Well I exported it and tried to re-add it to calibre and that did not work, then I tried to rename it to .azw and then try again, and still does the same thing. I must be missing something. This is really annoying though and I need my book on my tablet for school asap. If anyone wants to see the dumplog let me know because it does the same thing every time. Goes to parsing all content, does some stuff, then sits. I still haven’t broken 1% which makes me think this is impossible and it is really discouraging. This is one of the last things I get before it says something about going to try more forgiving values and then it just sits

    File “apihelpers.pxi”, line 1366, in lxml.etree._utf8 (src/lxml/lxml.etree.c:22211)
    ValueError: All strings must be XML compatible: Unicode or ASCII, no NULL bytes or control characters

    Forcing index.html into XHTML namespace

  10. Paul Durrant28 August, 2012

    azw4 files are Amazon’s “Print Replica” format, which are basically PDFs wrapped in a Palm Database. It sounds like the De-DRM is working fine, but you’re then trying to convert the PDF to Mobi, which is failing.

    Why not just read the PDF on your tablet? The main reason for publishers using Amazon’s Print Replica format is because the page layout is too complex for Mobi, and too time consuming for conversion to ePub/KF8.

    Just save it from calibre as a PDF and use that on your tablet.

  11. Strauzz28 August, 2012

    I got a azw file from Amazon. Earlier azw3 files have been no problem, but this one wont convert, even after reinstalling K4PC and calibre using revo uninstaller.

    I tried using the promt to insert the file inte calibre, this is what I got:

    C:\Users\Emillia\Documents\My Kindle Content>calibredb add B00813A60M_EBOK.azw
    Using Library AlfCrypto DLL/DYLIB/SO
    is not a valid Kindle serial number or PID.
    K4MobiDeDRM v0.4.2: Calibre configuration directory = C:\Users\Emillia\AppData\R
    searching for kinfoFiles in C:\Users\Emillia\AppData\Local
    No files have not been found.
    No K4PC 1.5.X .kinf files have not been found.
    No K4PC 1.6.X .kinf files have not been found.

    Trying: 4UC6KVNF

    Trying: h3IGl5/L
    Book Key Found!

    Processing Section: img
    . . . . . . . . . . . . . . . . . .
    Processing Section: color
    . . . . . . . . . . . . . . . . . .
    Processing Section: other
    Processing Section: dict
    Processing Section: glyphs
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

    Processing Section: page
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
    . . . . . . . . . . . . . . . . . . .
    Processing Section: metadata
    Successfully Extracted Topaz contents
    Updating to color images if available
    Creating cover.jpg
    Processing Dictionary
    Processing Meta Data and creating OPF
    Processing StyleSheet
    Using font size: 120
    Using page height: 12960
    Using page width: 8640
    Processing Glyphs
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

    Processing Pages
    . . . . . Running file type plugin K4PC, K4Mac, Kindle Mobi and Topaz DeDRM fail
    ed with traceback:
    Traceback (most recent call last):
    File “site-packages\calibre\customize\”, line 148, in _run_filetype_plugi
    File “calibre_plugins.k4mobidedrm.__init__”, line 117, in run
    File “calibre_plugins.k4mobidedrm.topazextract”, line 303, in processBook
    File “calibre_plugins.k4mobidedrm.genbook”, line 500, in generateBook
    File “calibre_plugins.k4mobidedrm.convert2xml”, line 764, in fromData
    File “calibre_plugins.k4mobidedrm.convert2xml”, line 731, in process
    File “calibre_plugins.k4mobidedrm.convert2xml”, line 513, in doLoop72
    File “calibre_plugins.k4mobidedrm.genbook”, line 120, in lookup
    TypeError: %d format: a number is required, not NoneType
    Backing up metadata
    Added book ids: 82
    Notifying calibre of the change

    So from the azw I got a tpz file and metadata.opf. Calibre wont convert tpz. Ive tried changing name to azw but that didnt work. Ive googled and can´t see a way to convert the file without using python. True? And is the file drm free?

    1. Twizzler30 August, 2012

      Received exact same error. If anyone has any ideas, please reply!

      1. Paul Durrant21 September, 2012

        That’s an indication that it’s a Topaz book with some info in i the developers haven’t come across before. There’s a new Tools v5.2 out now that might fix the problem.

  12. Jeff28 August, 2012

    If anyone cares I let it run for 2 hours before I went to bed and it seems fine. THanks for the help, it did convert, seemingly..

  13. Jenna31 August, 2012

    Don’t forget to hit “Apply” in the top left corner after loading the plugin!!!

    1. Jennie16 November, 2012

      Thank you! I did miss that. New to calibre. 🙂

  14. Andrew3652 September, 2012

    I followed instructions and managed to convert a mobi file to epub. However, when trying to convert the same file to pdf, I get the following message:

    calibre, version 0.8.67
    ERROR: Unhandled exception: TypeError:arguments did not match any overloaded call:
    QFontInfo(QFont): argument 1 has unexpected type ‘QString’
    QFontInfo(QFontInfo): argument 1 has unexpected type ‘QString’

    Traceback (most recent call last):
    File “site-packages\calibre\gui2\convert\”, line 252, in accept
    File “site-packages\calibre\gui2\convert\”, line 280, in commit
    File “site-packages\calibre\gui2\convert\”, line 107, in commit_options
    File “site-packages\calibre\gui2\convert\”, line 117, in create_recommendations
    File “site-packages\calibre\gui2\convert\”, line 146, in get_value
    TypeError: arguments did not match any overloaded call:
    QFontInfo(QFont): argument 1 has unexpected type ‘QString’
    QFontInfo(QFontInfo): argument 1 has unexpected type ‘QString’

    I am lost here… what should I try next? Thanks.

  15. Nathaniel Bronner3 September, 2012

    I have read a lot of online instructions before but this one was the absolute best one that I have ever read! Fantastic! Even the pics were clear with arrows pointing to the relevant parts. I could follow the instructions without a hitch but I would like to suggest one additional portion.

    You have correctly assumed that many people are quite technically illiterate therefore the instructions should assume nothing and clearly point out everything. I consider myself to be moderate to semi-pro level with computers but half of the people who I know are close to the illiterate level. Therefore for them perhaps the same step by step detail of the conversion process once in Calibre would be very beneficial.

    Most simply want to strip the DRM from their Kindle books which is what I wanted to do. Most will have never used Calibre. Calibre is an excellent program but it can take some study to figure exactly what to do to convert a book. That’s where the additional instructions would come in very handy. Most want to convert a Kindle book to a non-DRM’d book to also be read on the Kindle platform.

    Do they use AZW, mobi, epub, etc.? Of course they can only use the first two for Kindle but many won’t know that. If they want to convert a particular book, how do they find it in the Kindle folder since the file names are cryptic?

    If you have the time (there’s no question that you have the skill) perhaps a part two detailing exactly what to do once you are in Calibre would be greatly beneficial to the “other” half.

    I had actually purchased a Kindle DRM removal program which doesn’t work nearly as well or consistently as the method that you have outlined.

    Thanks a million for such a phenomenal tutorial.

  16. Margot10 September, 2012

    I have a Nook Color and a Mac computer. My friend gave me a gift card for so I bought a book and put it on my ‘Kindle for Mac’ but I want to convert it onto my Nook Color. I got the book put into Calibre but it won’t convert it because of DRM. I tried this tutorial and downloaded the zip file, but I am not seeing anywhere I can “load plugin from file” under preferences.
    Help, please?

    1. Margot10 September, 2012

      Okay so I got to install the plug in and I added my serial number from my iPhone that my Kindle is on and this is the screen (minus my serial number):

      What do I do now? I clicked “apply” then shut down Calibre then tried to convert my Kindle book to epub again and it still says it’s protected.

      1. Nate Hoffelder10 September, 2012

        You don’t need to enter any serial number. Just download the ebook to your PC with the Kindle4PC app and copy that ebook into calibre.

        calibre should be able to do the rest.

        1. Margot10 September, 2012

          Thanks. It worked! The book I bought is now in my Nook Color.

          1. Mary14 January, 2013

            What finally worked for me in converting my book to my Nook was to download the book again into Calibre from Kindle file on my Mac. At first, after I added in the plug-in, I kept trying to convert the book I had downloaded earlier into Calibre. I went back and added the book again and it had a AZW3 ending this time and it was converted. Finally!

  17. […] It's to get a DRM stripper plug-in to calibre so that calibre will automatically convert to .mobi. How to Add a Kindle DRM-Removal Plugin to calibre – The Digital Reader Basically it has worked. I'm not quite sure how I did it but following the various instructions […]

  18. Makenzie19 September, 2012

    Any idea if there is a way to remove nook drm to read them on kindle? I have a nook my son has a kindle. I can convert his books for me to use, but not my books for him.

    1. Paul Durrant21 September, 2012

      Yes, there is. Just get the free tools from Apprentice Alf’s blog.

  19. Michelle22 September, 2012

    Ok, i’ve downloaded calibre and gotten the tools and applied the proper plug-in. The books i’m wanting to deDRM are not registered to me, but to a friend of mine, she logged into her amazon account on my computer and i downloaded the books i wanted from her. With that being said, calibre still wont deDRM those books for me. What do i or can i do now? I’ m really wanting to read these books.

    1. Nate Hoffelder22 September, 2012

      If you downloaded direct from the Amazon website via a web browser then you didn’t follow the instructions. You need to download the files via Kindle4PC, and it has to happen on the same computer as the one which you are running calibre.

      1. Ralph Hummel22 September, 2012

        And also the K4PC app needs to be registered to the amazon account that you wish to download books from. So you need to register it really in your friend’s name on your computer. I’d be careful with this, as this effectively makes a copy of a book available on your machine that you have not bought…
        If your friend wants to remove DRM on her books for private use and to conserve the media, then I would suggest she instal Calibre and the plugin on her computer.

    2. Ralph Hummel22 September, 2012

      Buy them, or if you are in the US, subscribe to Amazon Premium and lend them (if they are available).

  20. Michelle23 September, 2012

    Ok, now my question is. Ive installed K4PC, if i have my friend register it on my computer, it makes a copy of the books available on my machine will i be able to deDRM them with calibre?

    1. Nate Hoffelder23 September, 2012

      You should be able to, yes.

  21. Michelle23 September, 2012

    I have one more inquiry. When i logged into K4PC with my own account info I noticed that in my kindle content folder there are no copies of any of the books that are on my kindle, but all of them are showing up on the K4PC, either in the archived part or the all items. What do i need to do in order to get the books to show in the folder?

    1. Ralph Hummel24 September, 2012

      You need to download them, K4PC does not automatically download yodur library to the machine it is installed on. You need to do this for every book.

  22. No 13 October, 2012

    Not working for me. Followed instructions. The file is an AZW file. Installed everything new. Loaded the plugins, clicked on Apply. Closed app, restarted, added book, no-go.

    When I try to add the book it gives me the error:
    No keys found in 0 tries

    I click OK and it continues to load the book. I have tried converting to PDF, MOBI, and EPUB, all with the default settings, and every time I get the Can’t convert, locked by DRM.

    Any other options?

  23. Trixie3 October, 2012

    Thanks for these instructions. I’ve been stripping with Calibre for awhile but haven’t been able to clean .azw3 files. I’ve got the latest plugins but doesn’t seem to work for me. Any tips?

    1. Rob4 October, 2012

      You need the latest Calibre version. Older Calibre versions don’t handle azw3 files.

  24. Jamie5 October, 2012

    I am definitely new to this so please bear with me. I have installed calibre. I have installed the plug in to strip the DRM into calibre per instructions above. I have added a book from my kindle device into calibre. I then attempted to convert the book (which apparently is in azw) to mobi and got a message saying the book was locked. I then attempted to convert the same book to PDF and got the same message – the book is locked.

    What am I doing wrong? Am I supposed to house the books somewhere else first and strip them? Help!

  25. digital reader fan5 October, 2012

    Right click on the plugin and type in your kindle serial number.

    Anyone know how to view in Calibre or if there is a plugin for a virtual bookshelf like this

  26. Jamie5 October, 2012

    A million thanks. It’s working!

  27. digital reader fan5 October, 2012

    You bet, sometimes you have to close the program out and re-open it for changes to take. Cheers.

  28. Andrew7 October, 2012


    I had Calibre and the plugins installed previously and they removed DRM from all ebooks. However, it stopped working, I assume because amazon updated their DRM.

    So I’m trying to update but things are not working.

    I have Calibre for Mac 0.9.1 installed.
    I updated Python to the newest version.
    I downloaded and installed the newest plugins.
    I restarted Calibre.

    When I try to add my amazon book with .azw format to Calibre, it tells me:

    Error decoding: /Users/macbookpro/Documents/Kindle Library/Fasting&Sunbathing.azw

    I have also tried undrming the file with DeDRM 5.3.2

    When I do, it says that I’ve successfully DeDRMEd the book.

    But when I try to load it into Calibre, it still doesn’t work.

  29. digital reader fan7 October, 2012

    Just checking if you have Plugin tools v5.3.1?
    I don’t know anything about Python. Just the Calibre Plugin’s. instructions in the ReadMe files on how to use them, from reading your post I’m sure you covered everything.

  30. Clueless8 October, 2012

    I am using Calibre version 0.9.1 with
    K4MobiDeDRM_v04.5_plugin. I am trying to remove the DRM from a .azw file. I entered the correct Kindle serial number, but I get the error message below. Any ideas of what I am doing wrong?

    Using Library AlfCrypto DLL/DYLIB/SO
    K4MobiDeDRM v0.4.5: Calibre configuration directory = C:\Users\Peter\AppData\Roaming\calibre
    MobiDeDrm v0.37. Copyright 2008-2012 The Dark Reverser et al.
    MOBI header version = 6, length = 248
    Extra Data Flags = 3
    searching for kinfoFiles in C:\Users\Peter\AppData\Local
    Found K4PC kinf2011 file: C:\Users\Peter\AppData\Local\Amazon\Kindle\storage\.kinf2011
    Using Volume Serial Number for ID: 2656441693
    Crypto Type is: 2
    Running file type plugin Kindle and Mobipocket DeDRM failed with traceback:
    Backing up metadata
    Added book ids: 7
    Notifying calibre of the change


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