Blender stopped rendering with cycles I'm following the donut tutorial and got to part 6, everything was going well and I was switching back and forth between eevee and cycles just fine until... it no longer will render cycles in the viewport.  I can still render images with cycles, but the viewport isn't working.
I tried closing and restarting my computer + restoring blender to factory settings.  I'm hoping theres a setting I'm messed up.
Ok I figured it out, the first clue was that I wasn't seeing a shadow on the plane even in eevee.  Turns out I was in 'solid mode' and not in 'render preview mode'.
Leaving this up in case it helps another beginner.