I'd be surprised if it had anything to do with restarting your machine...
Are you saving your scenes on your solver start frame?
It could be something like: your solver start frame is zero, but your timeline starts at 1. So when you reopen the scene, every time you rewind, you never give the solver a chance to initialize.
Otherwise if you can reproduce the error and send it to us we can take a look.
Did stdout have more info?