The IRS hasn't finalized one or more of your forms.

[carlos3786]

I've never encountered this before. How long does it take to get a response, on average?

[AndreaC1]

You will need to wait until the form you need is available, before you can file. You can see the full list of available and unavailable IRS Forms here https://ttlc.intuit.com/questions/1908854-irs-forms-availability-table-for-turbotax-individual-perso... and you will also see the date that they should be ready, if they are not already available. 

And you can go here to see state form availability https://ttlc.intuit.com/questions/1908857-state-forms-availability-table-for-turbotax-individual-per...