If you live in PA and work in DE, then Yes, you definitely have to file in both states. You must file a non-resident DE tax return and your home state PA return.
You'll be able to claim an "other state credit" on your PA return for the taxes paid to DE, so the net effect is that you won't be double-taxed. But you still must file a return in both states.
In TurboTax, be sure to complete the non-resident state return first, before you do the home state tax return, so that the program can calculate and apply the credit.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
