Ok, That might be an overstatement, but apparently since the first of April, this problem cannot be solved by the Amazon Kindle Engineer department. According to them, this has never happened before.
One day out of the blue my collections disappeared of my Kindles and the cloud. No warning, no user error. Just one day one Kindle stopped showing them, and the next day the other one followed suit. So, my 1000 plus book library is just out there with no organization. I have not only the cloud books, but a large ammount of downloaded from PC books.
I have tried everything, and have reset, restored, tried various techniqes for finding them. Can't find the old collections at all. Amazon has not deleted them either. They show up on my other devices. Devices I don't read on, but have the Kindle app. (although I have never been able to get them on my PC). Initially, when Amazon was trying to fix the problem they basically pushed through every collection I have ever made (deleted or not) and the populations within them and they showed up on these devices but not the two Paperwhites.
I can create new collections and they show up on the device it was made on as well as the cloud and other devices, but not the other Paperwhite. So, it's kind of pointless. No syncing defetes the purpose of having two devices (I just ended up with two because one got lost and then returned after purchasing a new one)
This would not be a huge problem except I have a vast library and I read my books daily. Without collections I am forced to rely on memory rather than Slooooowwwly wade through 1000+ books, both in the cloud and downloaded from my computer. Have you ever tried to browse your Kindle Paperwhite manually? Impossible.
This is why I use the collections (clunky and completly inefficient as they are already). I cannot jailbreak the devices to install Calibre Kindle Collections manager due to the new OS and firmware. I have been forced to generate a catalog from Calibre to refer to so that i know what I have and where I need to get it. This is an endevor that is ongoing, as now i have to completly edit each book in Calibre for tags, metadata, etc. before generating the catalog.
The Kindle Engineer department at Amazon hasn't figured it out, or hasn't tried hard enough because it has been ongoing. I suspect they think it is a problem with user error and I am dumbwit who just needs to do something to access them. I have actually been receiving regular updates from Customer Service Representative from Amazon for the past oh, two months now...He is so nice, he keeps telling me that he wish he could call and say "We did it!", but its been more of, "sorry, they still haven't figured it out yet."
I still can sync reading progress on the books, and have discovered a new perk that until now has never been able to be done before. Downloaded books from other devices (not in the cloud) sync between the two. I can read a book I downloaded off my computer that isn't in the cloud, and pick up the other device and the reading progress syncs.
OK, I know this isn't a rants forum, but I am hoping someone here can come up with a solution, or at least has gone through this.