Thanks for the advice. Switching the GPU to off didn’t help.
I don’t know how to set render to “CPU only”
I’ll look at graphic card updates. I think you’re correct that the problem is in the efx, and on a few of the crashes a message flashed saying the AMD card had ceased, and actually crashed the OS requiring a hard shutdown.
Actually the problem started after my upgrade to Vegas 15 from 13. I’ve uninstalled 15 and re-installed it once already.