Solving Simulation Errors
If you have designed a few circuits with Circuit Maker, then there is a chance that you have seen the "Matrix is Singular" message. You will not be able to run a simulation until you can find the cause of the problem. Here are a few tips:

1. Make sure that you have a valid input and output source selected.
2. Look around your schematic for a stray piece of wire. It may be highlighted in red, and delete it.
3. Check that no two capacitors are in series, if they are, then connect a high value resistor across one.
4. If you are using a current source try shunting it with a very high value resistance say 1T.
5. Turn on the node numbers, press F6. If you see a single wire with different node numbers, delete it.
6. Redraw this connection, it may solve your problem.
7. Make certain that you have a ground connection in your circuit.