Rapid switching, particularly in sim circuits involving inductance or zeners or varistors, often gives me this dreaded error message and the sim grinds to a halt. The ad hoc fix is sometimes just a matter of tweaking a component value slightly. Is there a generic solution, e.g. by setting some value in Control Panel / Spice, or by adding some directive on the schematic? I know there is the option to set a maximum time step (though I haven't fathomed what effect this actually has on the sim), but how about a minimum?