If you buy an e-book from the Amazon.com store and send it to multiple reading devices, chances are good that they will remember the last page read for that book between devices. This feature (sometimes referred to as “syncing”) doesn’t work if you “sideload” (directly copy a file from another device) a non-Amazon book. For instance, if I copy an e-book file from my computer to both my Kindle Keyboard and my Kindle Fire HD via the USB cable that book will not remember the last page read between those Kindles. So what is the solution? I know two ways to make this work.
Send to Kindle for PC
The first is using the “Send to Kindle” program provided by Amazon. You can download the program Send to Kindle for PC from the Amazon.com site. Once it is installed, and you register with your Amazon.com account information, it can be called up by right-clicking a file (formats: DOC, DOCX, TXT, RTF, JPEG, GIF, PNG, BMP, PDF or MOBI) on your PC.
Choose which devices to send to and be sure that the “Archive documents..” box is checked. Once this window is opened you can also drag-and-drop multiple files on it. “Send to Kindle” will also appear as a new printer in your Print menu, but if you choose this option it will always send a PDF document to your device(s).
To specifically use this to sync last page read on your books they need to be in one of the acceptable formats (MOBI, for example, will work fine). Just use the program to send a MOBI-formatted book file to your devices with the “Archive document in your Kindle Library” box checked. As a pop-up says, it may take several minutes for it to be delivered by Wi-Fi.
Calibre
The other way to sync your e-books is to use the Calibre e-book management program on your PC to convert your file to MOBI format. Even if you obtained the file already in MOBI format, use Calibre to re-convert it before sending to your devices. Also, if you are a long-time Calibre user and converted your files with a version of Calibre prior to 7.44 you need to re-convert those files with a newer version of Calibre.
To get the e-books to sync using Calibre just send the MOBI format file to your devices through a USB cable.
Summary
Both methods require installing and using a PC application. With “Send to Kindle” you don’t need to hook your devices to your PC with a USB cable and you can sync more formats. However, the books do pass through the Amazon cloud server. With Calibre, only the MOBI format will sync properly and the files are transferred directly to the devices via cable — by-passing Amazon.com entirely.