Same issue here on Raspberry Pi 2 with retropie 3 beta 2. On my system I have issues whenever I turned on the atari800/atarist emulators. If I rename them so emulationstation doesn’t find them everything is great, but if I include those two folders, I get a white screen on startup. The only way I’m able to reboot/access system is ssh remotely and reboot. I’ve tried turning on logging/etc same issue. I just rebuilt emulationstation from the latest git clone to no avail. Not sure whats going on, any ideas appreciated.

Update – renaming the themes so emulationstation uses a generic themes seems to have helped a bit, but still getting the occasional lockup.