Just because the system requirements say "OSX 10.12 or later" does not mean that it will not run in earlier systems, just that there is no guarantee that it will be accurate or continue to run after updates. What systems 2018 TurboTax will run in depends on what Apple development toots support and the Apple tools only support 10.12 or later. That does not mean that it will not run in earlier systems, just that it is not supported.
The post that dustymacaw made was a month ago before TT 2018 was even released so at that time it was just speculation and what was answered was the information available at that time.
BTW if you do not know, this is a user-to-user forum for tax discussion between TurboTax users and not TurboTax support. We are all just other TurboTax users.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
