What is this. Why did i just lose all my progress. And why does the software not even allow ctrl Z (undo). VERY FRUSTRATING
Did you try save/exit - go back in? basically if you can save and restart it should be fine.
I get this often when I'm running out of memory. You can still save (ctrl + s), close it, and re-open it and it will work. Alteryx also takes backups and you can recover it from that backup.