State tax filing

A Control Number (box D) is used by many payroll departments to uniquely identify a W-2 in their system.  If your W-2 doesn't have one, it's no big deal - you can leave this field blank.

If you get errors when attempting to e-file with an empty box D, just enter any number in this format: 5 digits, space, 5 digits (for example 12345 67890). The IRS doesn't care what's in box D.

If you get errors when attempting to import your W-2 with an empty box D, select Skip import and manually enter your W-2.  You won't be able to import using the above solution for e-filing.   @ewilth

If you have multiple state taxes withheld in Box 17 of your W-2, click on Add Another State underneath Box 15.   See the image below with wages sourced from 3 different states.