Your 2020 turbotax software DOES NOT have an "option M" in the 8829 Asset Entry Worksheet! Please advise, continue to recieve error
Have you updated your software?
The 2021 version of TurboTax has that option but I recall that there was some sort of issue with a previous tax year.
You might want to contact Support.
What is the TurboTax phone number? (intuit.com)