This might be a bug report, we'll see. When I try to simulate with the desktop tool I get Error: Not Found. There's no other result. I made the simplest possible circuit, with a battery, resistor, ground, and a probe. I've used the online tool before, so I kind of know what I'm doing. The big reason I wanted the desktop version is to remove the limitation on the number of simulations I can do... Any ideas? John May