This post for future reference as the problem seems unique:

So turned the key and only heard the fuel pump going and starter motor spinning, but the engine would not crank. Checked the battery and all was well.
My daughter and I found a 'mystery bolt' laying under the transmission that seemed to be related to the problem, but where could it have come from?
This hole:

Click to view attachment

It goes the the arm of the solenoid fork, which is why the starter was not engaging:

Click to view attachment

I was able to pull the arm back with a very small screwdriver, enough that I could get the bolt in through the top of the starter. (not easy!)

Tried the key and we're back in business! A good night..

BTW, starter sticker reads: "Remanufactued in Mexico". :^/