After you file

You wrote:  " I received a letter from the IRS stating that they did not received my 2017 state tax return. I know I filed but maybe they didn't receive my check."

 

The IRS handles a Federal return.    Was that a typo, and did you mean your state tax agency?   So please clarify if you are referring to a Federal return or a state return.  Is the letter from the IRS or a state tax agency?

 

"maybe they didn't receive my check"

Did you have taxes due that you paid by check that was never cashed?

 

Log into your online TurboTax account.   At the Tax Home go to the section "Your Tax Returns & Documents."  Expand that section and choose tax year 2017.    What is shown for the "status" of the 2017 Federal and state returns?