One is big and I've been working on it for about 6 months, it uses the steampunk texture Pack. The screen freezes at Initializing Server, Loading Soawn Area.
We downloaded an update and from that point on, we cannot load our game. We spent way too many hours for an update to screw everything up! Foldbenkenobi, My son and I are having the exact same issue as you.
My son and I are gutted and I hope someone can help. If there is a more appropriate place to post this, please let me know, thank you.
You do not have to be in a world to copy it to another destination.
I'm not sure either that merely saving to the cloud prevents it.
Keeping regular backups of your world on a separate device would mean that at least you could go back to a "uncorrupted" version of your world and start from that point. I only say this because I don't tend to use redstone very much at all in my worlds and, if I do have an build that uses a bunch of it, I make sure that is the only build that is using it in that world.