How to add EPUB, MOBI, and PDF files to your Kindle - no converting required

The Human Reaction to Losing Features

Isn't it funny how the human mind works? We often don't appreciate the features of a product or service until they're taken away. Take Amazon's recent decision to stop allowing Kindle ebook files to be downloaded to computers for backup. Many Kindle users didn't even know this feature existed until it was announced that it would be gone by February 26, 2025. Yet, the reaction has been swift and fierce, especially from collectors who relied on this functionality.

For owners of older Kindles, this change hits hard. The first and second-generation Kindles, as well as the Kindle DX, could only transfer data wirelessly via the now-defunct 3G networks. The only alternative was a USB connection to a computer. Even with slightly newer models, like my wife's old Kindle Fire 7 from 2011, transferring files can be a hassle. After deregistering it to switch to my account, I couldn't get it to register again, despite help from Amazon's tech support. So, for devices like these, USB remains the only way to load files.

In this article, we'll delve into the process of transferring files—Kindle files and other popular ebook formats—to both old and new Kindle devices. But first, a crucial warning:

Never Deregister Your Old Kindle

If you've managed to download your Kindle books before the cutoff date, remember that many of these books are protected by DRM. They'll only work if both the device and the book are registered to the same Amazon account. My wife tried loading a .azw file she had downloaded onto an unregistered third-generation Kindle from 2010, and it resulted in an error.

David Gewirtz/ZDNET

Here are some key points to keep in mind:

• You can no longer transfer books wirelessly to the Kindle 1, Kindle 2, and DX.
• You can't download Kindle books to your computer anymore.
• But if you've downloaded Kindle books before the February 2025 cutoff, you can still upload them to discontinued or current devices via USB.
• Deregistering a Kindle 1, 2, or DX means you can't re-register it due to the lack of connectivity options. This is a major no-no if you want to read downloaded books.
• Even with Wi-Fi enabled older Kindles, deregistering might prevent re-registration due to outdated security protocols.
• As long as your old Kindle remains registered to your account, any downloaded books should be compatible.
• Some newer format Kindle books won't work on older devices because they can't read the newer formats, even if both are registered.

So, if you want to keep using your older Kindle, never deregister it. And think twice before gifting it to someone else, as they won't be able to register it.

Transferring Files to Your Kindle via USB

Now, let's get into the nitty-gritty of transferring files to your Kindle via USB. First, gather your cables. All Kindles from the first generation onwards can be mounted as USB drives. Here's what you'll need:

• Mini USB for Kindle 1.
• Micro USB for Kindle 2 through Kindle Oasis 3 (2009 to 2017 models).
• USB C for all Kindle models from 2018 onward.

Not all cables will work, so be prepared to try a few. We found success with cables from Monoprice and Amazon Basics. If a cable doesn't work, keep trying until you find one that does. And look for "Free Returns" options when buying cables.

Mounting Your Kindle as a Drive on Windows

On Windows 11, the process is straightforward. Just plug your Kindle into your Windows machine with a USB cable, and it should mount as a drive. Drag your ebook files into the Kindle>Internal Storage>documents directory. Older Kindles might have the documents directory at the top level. When you're done, simply unplug your Kindle—no need to eject.

Screenshot by David Gewirtz/ZDNET

Mounting Your Kindle as a Drive on Mac

The process is similar on Mac for pre-2024 Kindles (except the Scribe). Just plug in your Kindle, and it should mount as a drive. But for the Scribe and 2024-and-newer Kindles, you'll need to use the Send-to-Kindle for Mac application. Download the installer from Amazon's ConnectMyKindle page, run it, and sign into your Amazon account.

Screenshot by David Gewirtz/ZDNET

After installation, you'll find a Send to Kindle folder in your Applications. Plugging in your Kindle will launch the Send to Kindle application. You can drag and drop files into this interface, but if you encounter errors, use the Open USB File Manager button to access a Finder-like window for transferring files.

Screenshot by David Gewirtz/ZDNET

Screenshot by David Gewirtz/ZDNET

Screenshot by David Gewirtz/ZDNET

Screenshot by David Gewirtz/ZDNET

What Formats Work on What Kindles?

I tested various formats on an unregistered Kindle Keyboard (3rd generation) from 2010 and a current-generation basic Kindle registered to my account. Here's how different formats performed:

David Gewirtz/ZDNET

AZW and AZW3

I knew the AZW file from Denise was DRM-locked and wouldn't work on either device. However, transferring the AZW3 file via USB worked perfectly on both. Remember, DRM can apply to both formats, so an AZW3 file isn't a guaranteed bypass.

EPUB

I purchased "Potus" by ZDNET's Jack Wallen from Smashwords as an EPUB. I couldn't transfer it to my current-model Kindle via USB, but using Amazon's Send to Kindle page, I successfully sent it to my device.

Screenshot by David Gewirtz/ZDNET

Screenshot by David Gewirtz/ZDNET

Screenshot by David Gewirtz/ZDNET

However, this method didn't work for the unregistered Kindle 3rd generation or the Kindle 1, 2, and DX, which lack wireless connectivity. Converting the EPUB to MOBI format is a workaround, which I detail in another article.

MOBI

I downloaded "20,000 Leagues Under the Sea" from ManyWords in MOBI format. While Send to Kindle wouldn't accept it, I successfully transferred it to both my current-model Kindle and the old Kindle 3 via USB.

PDF

I tested with the Verizon 2024 Data Breach Investigations Report. Both the current-model Kindle and the old Kindle 3 could transfer and read the PDF via USB, with nearly perfect formatting. I also used Send to Kindle and Deliver to Device on the current model, which worked well.

DOC and DOCX

I used random documents from my personal folder to test DOC and DOCX. On the current-model Kindle, neither format appeared when transferred via USB. However, I successfully transferred the DOC file using Send to Kindle and Deliver to Device. The DOCX file worked after resaving it in Word with compatibility options.

The old Kindle 3 couldn't read either format when transferred via USB. For more on converting these files, check out my article on format conversion.

Your Preferred Method?

Have you ever transferred books to your Kindle via USB? What challenges have you faced with different file formats? Do you prefer USB transfers or Amazon's Send-to-Kindle service? If you own an older Kindle, have you discovered any workarounds to keep it running? Share your experiences in the comments below.

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