Originally Posted by ficbot
How do I register it with a Windows machine? I am at the Adobe Digital Editions website and see nothing about that...
From Adobe Forums
First, on the same Windows machine that you upgraded your Sony Reader, install ADE and authorize it to your AdobeID.
Next, plug in your Sony Reader and then in ADE, select the Reader and choose "Authorize Device" from the Library menu (I'm doing this from memory, and I don't have a Sony Reader to test it on right now - so the wording may be off).
At this point you have a Sony Reader which is authorized to your AdobeID. For any eBooks you purchase on the Mac (with ADE 1.5 authorized to the same AdobeID), you will be able to copy the .pdf/.epub files to your Sony Reader, using the Finder, and then be able to view then on your Sony Reader.
I don't think the "upgrade"software part is necessarily needed, but perhaps you need Sony eBook library software too.