only taxpayers in Maine and Massachusetts have until 11:59PM state time on 4/17 to e-file their federal sane state extension. (not sure about out of state extensions). That's because of the state holidays on 4/15 and 4/16. Turbotax may not have been programmed to allow for this. If you qualify and can't e-file you'll have to file by mail and give Turbotax 5 thumbs down.
