@ collinbrent
You wrote: "I am attempting my file my rejected 2018 taxes but the TurboTax cd keeps giving me an error message saying that the file failed to transfer. All I need to do is change my adjusted gross income."
Was that 2018 return originally prepared in Online TurboTax or desktop software? If it was prepared online, then you do NOT "transfer" a *.tax2018 data file into the 2018 software. When you launch TurboTax, if the program is looking for a file to transfer into the program, it is looking for a 2017 return to transfer into a new 2018 return. And that's not what you need to do.
However, if you have a rejected *.tax2018 data file that was prepared online, and if you need to make any changes in it before filing, you can OPEN it in the 2018 software. To do that, launch your 2018 CD program. At the main screen, go way up to top left corner of the TurboTax interface and click on the FILE menu, and in the dropdown choose OPEN tax return. Then point the program to the location of the *.tax2018 data file.
However, are you asking about 2017 AGI in order to efile? Is that all you're wanting to do? If so, there's no need. You cannot efile it, so if that's what you meant, you do not need a 2017 AGI as Hackitoff mentioned above. You have to print, sign, date, and mail. If you have both Federal and state returns, be sure to mail the Federal to the IRS, and the state return to the state tax agency. And as Hackitoff said, it's best to mail with a method that has tracking such as certified return receipt, priority mail, etc.
