downloaded zip files do no open on my PC

I have a zipped back up file on my icloud account which I downloaded on my PC. This however does not open - message i get it that the zip file is invalid. I note that many many people are facing this problem and not much response from the community (lol) but thought I will post this anyways in case someone has found a way around the usual apple attempts at making life difficult for anyone who wishes to use non ios systems/storage etc etc.