Filing 2016 1040 prior to January 31, 2018. I am in Houston and therefore, have an extension to that date. How do I keep TurboTax from computing a late filing penalty?

First, you cannot use TT Online to file a 20916 return now,.

And the program doesn't compute a late filing penalty ...only the IRS can do that.  What is being calculated is a late payment penalty because the extension was only for more time to file not more time to pay.  You should have paid the estimated balance due with the extension.

Thanks for the very helpful response. I was aware of the necessity of filing a paper return

TurboTax will not compute a late filing penalty.  Only the IRS does that.  Since you are filing from a hurricane area, the IRS will recognize that and you will not face a late filing penalty.

 Online preparation and e-filing for 2016 is permanently closed.  You have to download 2016 software and then print, sign and mail your return.  If you already paid for your TurboTax software, you can contact customer support to push a download of the software to you.

To call TurboTax customer support

https://ttlc.intuit.com/questions/1899263-what-is-the-turbotax-phone-number

They are available Monday-Friday from 5 a.m. to 5 p.m. Pacific time.

To finish a prior year return started in TT online:https://ttlc.intuit.com/questions/2559403-how-do-i-finish-a-prior-year-return-that-i-started-in-turb

When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s.  Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS received the return.

Thanks--very clear and helpful response.