Just downloaded the latest version of the Media Creation Tool on two different PCs, one brand new and the one I'm posting from. I'm getting the same error message at the startup screen on both.
I have tried what I've found documented out there in cyberspace (by the way, I have no "Unblock" option in General Properties).
Just wondering if anyone knows if this is a temporary and recurring problem on Microsoft's end? I have never had this issue with the Media Creation Tool at any time in the past. Perhaps I was just lucky.