When I boot MBU it changes the resolution to 800x600 and then immediately crashes. Has anyone experienced this? If so does anyone know a solution? I already reinstalled and the same problem happens

Funny you mention that, I just had the same issue and resolved it.

In appdata/GarageGames/MarbleBlast/userprofile_pref1.cs, line 159 has pref::video::resolution, which you should change to your screen resolution. Near that line, you can set fullscreen=0 and enable vsync if that doesn't immediately resolve the issue.

Thanks! This worked immediately.