What is a D400 form and why can't I file now?

[DoninGA]

Form D-400, Individual Income Tax Return Main Form is estimated to be finalized in TurboTax on 01/27/2022

Go to this TurboTax website for North Carolina state forms availability - https://care-cdn.prodsupportsite.a.intuit.com/forms-availability/turbotax_nc_online_individual.html

[MinhT1]

Form D-400 is the North Carolina state tax return.

This form is not yet available.

Please see the availability list for North Carolina tax forms.

[SteamTrain]

...........ANNND, NC has recently announced that it is delaying all tax processing until the middle of February (no specific date). 

During that time, they will also have to update their computer interactions with the various software companies....and TTX is currently estimating 3 MARCH for being able to e-file your NC tax return.   Could be sooner if things go well, but right now 3March is when they expect to be able for you to efile NC taxes.