Sorry you can’t use Turbo Tax to prepare or amend 2020 even if you filed from Turbo Tax. They only support the last 3 years.
Even if you find or reinstall the Desktop program, you will never be able to activate the 2020 program with the License Code. The License Code started in 2019. So it needs to connect to Turbo Tax to verify the License Code. But they have stopped supporting 2020 and prior.
Really? That's sounds like poor customer service. So there is hi way to amend a 2020 return?
You can either locate a tax professional in your area to assist you in amending the 2020 tax return.
Or -
You can go to the IRS website for the 2020 federal amended tax return, Form 1040-X, and complete the form manually. The amended return can only be printed and mailed.
IRS Form 1040-X (20220) - https://www.irs.gov/pub/irs-prior/f1040x--2020.pdf
Unfortunately, no, not with the TurboTax software. Generally, to claim a refund, you must file an amended return within 3 years after the date you filed your original return or 2 years after the date you paid the tax, whichever is later. If you filed early, count from the April tax deadline.
Special rules apply to file for refunds when you have net operating losses, foreign tax credits, bad debts, and other issues. You may have more time to amend for:
Find details on when to file an amended return