A state return can still be efiled by itself after the Federal return IF the Federal return was efiled previously and accepted.
If the Federal return was filed by mail, however, then the State return has to be mailed as well.
We can tell the user how to open the return back up to finish and file the State return, which may be able to be efiled if the Federal return was efiled. But user first needs to answer the questions I asked in my comment above so we can know how he/she originally filed the Federal.
