KFX conversion, transfer back to library issue.

[shoelesshunter]

Hi, I hope I have the corrent forum.

I have been successfully converting my epubs to KFX using the plugin. The issue is that once said file is side-loaded onto my Kindle, I can't transfer it back into (another or original) Calibre.

Is there a way to enable Calibre to import its own KFX files?

thanks.

[jhowell]

calibre does not currently support importing KFX format. The easiest way to accomplish this is to copy the book from the original calibre library to the one where you want it using calibre's "Copy to library" function.

As an alternative you can use the "Add books" function and manually select the "documents" folder on your Kindle and set the file type to "All files" instead of "Books". But doing it this way will not import any of the book metadata.

[shoelesshunter]

Thanks. The metadata is no problem I only have 8 books in this format.

[madelonw]

Originally Posted by jhowell

calibre does not currently support importing KFX format. The easiest way to accomplish this is to copy the book from the original calibre library to the one where you want it using calibre's "Copy to library" function.

As an alternative you can use the "Add books" function and manually select the "documents" folder on your Kindle and set the file type to "All files" instead of "Books". But doing it this way will not import any of the book metadata.

I hope my experience getting KFX books into Calibre without using Kindle for PC will be helpful.

This method is for books purchased after February 26, 2025. I "purchase" freebies daily, so I had quite a few books in Content and Devices to deal with. This works once you have installed DeDRM 10.0.9 in Calibre. This method does not use any version of Kindle for PC.

1. Send books to your Kindle device (I can't say whether this works if you don't have a device)
2. Once the books appear as downloaded on the device, plug the device into your computer
3. When the File Explorer window opens, navigate to documents > Downloads > Items01
4. Select all the books with the KFX extension. (If you are reading a book in the list, deselect it - [Ctrl + click])
5. Open Calibre and drag and drop the selected books to Calibre. The new entries should have a KFX format.
a. If you see a KFX.ZIP format, you need to delete that item and resend it to your device.

At this point, I delete the books from my device that I just dropped into Calibre. Your Kindle device needs to be plugged into your computer otherwise you will need to delete them from the device one by one. If you are playing catch up, as I am, you might want to delete these books as well. If you delete the books, you should also delete their corresponding folders. Once you have made these deletions, eject the Kindle device. I use Eject this device from the Device dropdown in Calibre.

You must copy (drag and drop) books from your Kindle device directly into Calibre or this method will not work. If you copy them into a folder on your computer, they will import as KFX.ZIP. You cannot convert or open these files.

If you use the Count Pages plugin, it doesn't (yet) work with the KFX format. However, you can convert KFX books to MOBI (or EPUB) to use Count Pages.

I have used this method to add 395 books to Calibre. Once added I was able to convert all but 3 to MOBI format and Count Pages. Of the 3, only 1 produced an error message during the attempted conversion. I was able to open 2 of the 3 in the Calibre built-in ebook reader.

My Environment
Calibre 8.1.1
Windows 11 PC
Kindle 11th Generation (Firmware: 5.17.1.0.3 (4351890007)
DeDRM 10.0.9

For those of a more technical bent than I, here's the error message on that 1 book:

Calibre Convert Books Error
calibre, version 8.1.1
ERROR: KFX conversion failed: <p><b>Cannot convert The Murder of Mary Takahashi: A Shocking True Crime Story</b><br><br>Exception('section c17G, $269 987, story l17J, $269 991 has invalid text content: All rights reserved\\n\\nWhile every precaution has been taken in the preparation of this book, the publisher assumes no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. \\n\\nTHE MURDER OF MARY TAKAHASHI \\n\\nFirst edition. November 2020. \\nCopyright \\xa9 2020 Rod Kackley. Written by Rod Kackley. \\n\\n\\nSome aspects of The Murder of Mary Takahashi, some scenes and dialogue, names, and characters, have been fictionalized. \\n\\nHowever, there should be no doubt that the events detailed in the story you read in this book did occur. This is a shocking true crime story.\\n\\nCover Design: SelfPubBookCovers.com/Joetherasakdhi\\x0c')</p>

[JSWolf]

What you need to send KFX to your computer is calibre 8.x. (as of today the current calibre is 8.2.1), DeDRM Alpha, KFX Input, and KFX Output.

You plug your Kindle into the USB port
Drag/drop the .kfx file from the Kindle to your calibre library

YOU DO NOT COPY THE .KFX TO THE COMPUTER OR YOU WILL NOT HAVE A COMPLETE KFX EBOOK. KFX come in multiple files. When you drag/drop directly from the Kindle, the KFX Input plugin will grab the other files and add them to the KFX file so you will have a complete eBook in calibre.

This is the same if you are using K4PC. Drag/drop from the source directory to your calibre library. no copying first.

[DNSB]

You can also use Add books to add KFX format books either from a Kindle or K4PC.

[Highroller]

Unfortunately, Calibre can’t import KFX files that are already on your Kindle.

[DNSB]

Originally Posted by Highroller

Unfortunately, Calibre can’t import KFX files that are already on your Kindle.

That seems rather odd. I just connected my Kindle PW4 to my computer, clicked on Add Books in calibre, browsed to \documents\Downloads\Items01 and selected 3 KFX files. Clicked on Open and they were added to calibre. No muss, no fuss. Usual smaller B&W cover images but then they get replaced during editing the metadata. Converted one to ePub using From KFX and it opened in Sigil without the complaints about missing DOCTYPEs, etc. that a calibre conversion pops up.

I was wondering why we are suddenly posting in thread that was last active in 2017 but necroposting can be fun.

And to respond to JSWolf's reply, you do not need the KFX Output plugin to import KFX files since it is only needed when creating KFX files.

[madelonw]

UPDATE: Books sent to your device from an outside source via email are not delivered to your device as KFX but as AZW3. Only Kindle books from your library are now delivered by Amazon in the KFX format. I just had a book delivered this way from NetGalley.

Originally Posted by madelonw

I hope my experience getting KFX books into Calibre without using Kindle for PC will be helpful.

This method is for books purchased after February 26, 2025. I "purchase" freebies daily, so I had quite a few books in Content and Devices to deal with. This works once you have installed DeDRM 10.0.9 in Calibre. This method does not use any version of Kindle for PC.

1. Send books to your Kindle device (I can't say whether this works if you don't have a device)
2. Once the books appear as downloaded on the device, plug the device into your computer
3. When the File Explorer window opens, navigate to documents > Downloads > Items01
4. Select all the books with the KFX extension. (If you are reading a book in the list, deselect it - [Ctrl + click])
5. Open Calibre and drag and drop the selected books to Calibre. The new entries should have a KFX format.
a. If you see a KFX.ZIP format, you need to delete that item and resend it to your device.

At this point, I delete the books from my device that I just dropped into Calibre. Your Kindle device needs to be plugged into your computer otherwise you will need to delete them from the device one by one. If you are playing catch up, as I am, you might want to delete these books as well. If you delete the books, you should also delete their corresponding folders. Once you have made these deletions, eject the Kindle device. I use Eject this device from the Device dropdown in Calibre.

You must copy (drag and drop) books from your Kindle device directly into Calibre or this method will not work. If you copy them into a folder on your computer, they will import as KFX.ZIP. You cannot convert or open these files.

If you use the Count Pages plugin, it doesn't (yet) work with the KFX format. However, you can convert KFX books to MOBI (or EPUB) to use Count Pages.

I have used this method to add 395 books to Calibre. Once added I was able to convert all but 3 to MOBI format and Count Pages. Of the 3, only 1 produced an error message during the attempted conversion. I was able to open 2 of the 3 in the Calibre built-in ebook reader.

My Environment
Calibre 8.1.1
Windows 11 PC
Kindle 11th Generation (Firmware: 5.17.1.0.3 (4351890007)
DeDRM 10.0.9

For those of a more technical bent than I, here's the error message on that 1 book:

Calibre Convert Books Error
calibre, version 8.1.1
ERROR: KFX conversion failed: <p><b>Cannot convert The Murder of Mary Takahashi: A Shocking True Crime Story</b><br><br>Exception('section c17G, $269 987, story l17J, $269 991 has invalid text content: All rights reserved\\n\\nWhile every precaution has been taken in the preparation of this book, the publisher assumes no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. \\n\\nTHE MURDER OF MARY TAKAHASHI \\n\\nFirst edition. November 2020. \\nCopyright \\xa9 2020 Rod Kackley. Written by Rod Kackley. \\n\\n\\nSome aspects of The Murder of Mary Takahashi, some scenes and dialogue, names, and characters, have been fictionalized. \\n\\nHowever, there should be no doubt that the events detailed in the story you read in this book did occur. This is a shocking true crime story.\\n\\nCover Design: SelfPubBookCovers.com/Joetherasakdhi\\x0c')</p>

[JSWolf]

Originally Posted by madelonw

UPDATE: Books sent to your device from an outside source via email are not delivered to your device as KFX but as AZW3. Only Kindle books from your library are now delivered by Amazon in the KFX format. I just had a book delivered this way from NetGalley.

Sorry, but that's not accurate. I have a Kindle Touch and any eBooks delivered to it are in Mobi and mostly KF8. I will never get KFX as it doesn't support KFX. So your generic use of Kindle is incorrect. You need to say something like PW2 and later will get KFX.