Deductions & credits

If the return is already filed, and if it gets accepted then you will need to amend the return.  I have not seen this experience with a box checked automatically.  The question is asked in the Personal or My Info section.

If your return is rejected for any reason you can fix it and resend immediately through e-file.

Here are the steps to uncheck the box once you file an amendment.  Do nothing until the amended return is ready for use which will be March 25th in TurboTax.  It's important that your return is fully processed by the IRS.  Form 1040X

• How to amend (change or correct) a return already filed (and accepted at the IRS)
  • Review the information here to be sure you need to amend your return.
• Steps to amend my 2020 return

1. Sign into your TurboTax return > Personal Info > Review > Edit next to your name > 
2. Scroll to question 'Someone else can claim me as a dependent on their tax return.' > change your answer
3. Federal Review tab at the top to enter your stimulus information.

[Edited: 02/22/2021 | 5:30a PST]