You can mail the amended 2016 tax return at the same time as you mail the 2017 tax return, but use different envelopes (some people will put the two separately enveloped tax returns into one bigger envelope to mail, but it may be easier just to mail them separately).


Did you prepare the 2016 tax return with ProSeries?  If not, enter it into the 2016 ProSeries exactly has the original tax return shows.

After you have the original 2016 tax return in ProSeries, BEFORE you make any changes for the amendment, open the 1040X *AND* check the box for the year (2016).  Be sure you are using the 2016 software.  That will 'activate' the 1040X.  Do the same for any State amendment form.  THEN make any necessary changes on the 'regular' forms and worksheets for the amendment.  Do not make any changes before checking the year box to 'activate' the 1040X (the name, address, etc. will show up on the 1040X when you activate it by clicking the year box).