So, I've been having this problem.
I recently bought Universe Sandbox, and since I have a mac, played it in a Windows 7 Virtual Machine.
It started up just fine.
But this was the first time I tried. I tried the day after and it instantly crashed, and this was a few months ago.
So about 2 days ago I tried again, and it said it had an update. Hoping this would fix it, I updated. Still, it crashed.
I have tried everything from reinstalling .Net 4 to updating DirectX.
I have contacted Dan Dixon, (teh creator of US) and he told me to open up a topic on the "Universe Sandbox 2 Help" thread, because he had no clue what was going on, so here I am.
Until I find a solution, I'll just have to play the (awesome) RScience Mod for Powder Toy and make little Graviton Planets.
Thank you for your time,
Utopastoo.