did you use the 2017 software. that is the only software that can open the file.
if you can't open it, all is not lost, you can always go to IRS website and get transcript of 2017 which will show AGI reported.
If you prepared in TurboTax Online, here is how to access your prior return:
1. Make sure you’re signed in to your TurboTax account you used last year.
2. Select Tax Home from the left menu.
3. Scroll down to Your tax returns & documents and select 2017.
4. Select View adjusted gross Income (AGI)
If you prepared your tax return in TurboTax CD/Download, it should be saved on your computer.
If you prepared your tax return through other software, you can request a transcript from the IRS.
Follow this link: Get a Transcript
If you filed your tax return after October, 2018, use $0.