When I got my new computer it was automatically printing the tax forms in duplex (both sides), I had to turn off that feature in my Printer options to get it to print single sided....its not forced one way or the other.

I was not able to change the 2 sided printing by forcing the 1 sided option on my printer.

You may want to look on your printers manufacturer website for how to turn off Duplex printing...I cant find any PS setting that would force duplex printing....Ive been using the program for decades, its never printed duplex until I got a new computer (last Dec) and found I had to change the Duplex setting in the printer options in Windows.

Its possible that you have to restart the program or the computer after youve changed the printer setting in order for the program to recognize the change.