First, make sure you have only ONE (1) Turbo Tax file. If you have several state files, save others to another location in your computer, so that when you open Turbo Tax, there is only ONE file.
During e-filing, e-file Federal Tax only first. It's free. (choose mail-in for the state return)
Once Federal Tax return filing finished, go back and e-file the state return. When Turbo Tax pop-up box asks for "username/password", choose "continue as a guest" at the bottom.
Provide your info (name/address/credit card).
Done!
Happy filing.
