Solved
The IRS allows e-filing of amended returns now. Why won't TurboTax allow me to do this?
The ability to e-file an Amended return for 2020, closed in October 2021. The reason is because, after e-filing shuts down for the current tax year, we're working hard to get things ready for the upcoming tax year. You will be able to e-file your Amended 2021 return, this year.
Please see this TurboTax FAQ for more information, Can I e-file 2020, 2019, or earlier tax returns?
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