cmathieson,
Sound like a TurboTax bug/oversight. I can suggest a few things to try:
(a) pick any county to proceed, then later edit the CA return and see if you can reset it to blank.
(b) pick any county to proceed, then use the Tools->Forms option to go to a CA worksheet or form and erase the county name if possible.
(c) pick any county to proceed, and choose to print and US mail the return and use white-out to blank the field.
