[Liesse]

Just tried out this program for the first time. I am running the latest firmware on a UK wifi Kindle. I move my books to my Kindle using Calibre.

I like the interface; I found the icon showing that some files in a folder were not in collections very useful.

I'd like to suggest that .mbp and .apnx (memory on the second one, it started with an A) which I think might be calibre or kindle generated files, not show up in the manager. They aren't books.

I had a problem with several books in collections showing up without titles, just as a blank book icon.

I created two new collections and moved books into them. I also moved some new books into existing collections. However, upon saving and restarting my Kindle, the new collections didn't exist, and my books were not moved where I'd put them.
I also noticed the program reporting several books that I KNEW were in collections as not being; I dragged these over to the collections I wanted them to be in.

Brilliant idea and a tool like this that the writer regularly updates is very much needed. Its not working for me at the moment, but please keep working on it.

Incidentally, Kindle collection manager does not work for me either.