How do I proceed with my taxes when it's asking me for a value for a box 17 in my 1099-INT, but there is no value there?

Go back into the 1099-INT entry screen and remove any values entered for Box 15 (State) and Box 16 (State ID number).  To do this:

1. On the Wages & Income screen, in the Interest and Dividends section, click the Start/Revisit box next to Interest on 1099-INT.
2. On the next screen, click Review next to the 1099-INT you've entered.
3. Click the box My form has info in other boxes (this is uncommon).
4. Check your entries in Boxes 15, 16, and 17.  Then click Continue.

If you are still getting the error message, delete the 1099-INT and reenter, leaving boxes 15, 16, and 17 blank.  To delete a form in TurboTax Online, please follow these steps:

1. While in your return, click on Tax Tools > Tools (in the black bar at the side of your screen).  
2. In the Tools Center, under Other helpful links click on Delete a form.
3. Click Delete next to the form you want to delete and follow the onscreen instructions. 
4. Once you have finished deleting the desired form(s) click the Continue with My Return box (in the lower right of your screen).

@Irene2805 

I'm having the same problem. I talked to my bank and they confirmed that there was no tax withheld.

In that case, shouldn't I put a 0 in that box, instead of deleting the data in boxes 15 & 16?

Thanks for your help!

No, you would need to delete as directed by @Irene2805.