I'll tell you how to phone TurboTax Support so you can tell them you bought the 2016 desktop product and ask them to unlock your online returns.
So your 2012 return was prepared online and is locked in the Tax Timeline? Only online returns are going to be in the Tax Timeline.
2016 Home and Business can only open a *.tax2016 data file. It cannot open a *.tax2012 data file. One would need the desktop 2012 Home and Business to open the *.tax2012 data file. You would be able to view the 2012 PDF, however.
