State tax filing

Delete your Illinois and Massachusetts W-2s. Those are supplements to your main New York W-2. Rather than creating an IL and MA W-2, add the state information in lines 15-20 on your NY W-2 so it has three state lines – NY, IL, and MA.

1. Type w-2 in Search (magnifying glass) in the top right corner
2. Select Jump to w-2
3. On “Your W-2 info so far,” delete your IL and MA W-2s
4. Edit your NY W-2
5. Below NY, tap +Add another state and add additional state (and local, if applicable) lines for IL and MA
6. Go through each state again to make sure everything is correct.

Other state tax credit

Your title says “part-year resident tax filing.”  However, it sounds as if you were a full-year resident of NY. In that case, file nonresident returns for IL and MA. New York will give you credit for tax paid to IL and MA.

TurboTax CD/Download should update your credit amounts automatically but select EDIT next to each state in the “Other State Tax Credit Summary” to verify the income being taxed and the amount of tax paid.