Imagine you run a simulation over night, or you leave your desk for a coffee break. You come back later and your simulation has ended already but you want to see if the simulation has run to completion or if there was any error? You might also want to know if your simulation ended because you reached the end of simulation time as you set in the solver or it is stopped because you reached the auto shutoff level.
When you run a simulation, software automatically saves a .log file with the same name as your simulation file in the same directory. You can open up this text document and review the details of the simulation that includes mesh, simulation time, possible errors, and the updates about the simulation progress. This should help you to know what happened to simulation in your absence.
We have discussed about the auto shutoff level before here and here. So, if you want to know if you reached the auto shutoff level, look for a message says: Early termination of simulation, the autoshutoff criteria are satisfied in the log file as is shown in the image below!