@landerr wrote:
Will 2020 Turbotax Premier run with OS High Sierra version 10.13.6?
No. The minimum software requirements for the 2020 TurboTax software on a Mac is Mojave 10.14 or later
See this TurboTax support FAQ for the Mac minimum requirements - https://ttlc.intuit.com/community/system-requirements/help/minimum-system-requirements-for-turbotax-...
If you do not want to upgrade your software you can still use the TurboTax online editions - https://turbotax.intuit.com/personal-taxes/online/
If you used the TurboTax desktop editions for tax year 2019 you can transfer the 2019 tax data file to the 2020 online tax return.
See this TurboTax support FAQ for transferring tax data to the online editions - https://ttlc.intuit.com/community/entering-importing/help/how-do-i-transfer-last-year-s-return-into-...
