[mobilemoxie]

I'll give you general guidelines to follow in loading Kindle ebooks to Calibre; I just learned this myself in working with Calibre and plugins and suffered through troubleshooting:

1. eBooks you want to convert are best loaded into Calibre AFTER you've added your plugin(s) and restarted Calibre.

2. Any book you purchase from Amazon MUST be opened in an Amazon Kindle app, whether that's on your PC/Mac or other device that runs the Kindle software. It is the opening of the ebook in the Kindle app that 'sets up' the ebook and gives it the initial permissions. Without this step, Calibre won't be able to work with the file. This step is important for #3 below.

3. If you're going to load an ebook you purchased on Amazon into Calibre for conversion to another format, you need to do this *after* downloading/loading and opening the ebook on the Kindle app -AND- use the updated ebook file created and stored in the 'My Kindle Content' folder to load into Calibre.

It can take a bit of digging to find where the folder 'My Kindle Content' is stored on your computer or device, but it's this ebook file you need to load into Calibre. The file suffix will be .azw or .azw3 or something like that. The file name will be a bunch of letters that won't make any sense. Calibre knows how to input and read an .azw type file. You can drag that azw file into Calibre and it will load the ebook for you.

Hope this helps you work with Calibre and plugins and ebooks.