Here are the system requirements to install Turbo Tax for MAC…..
https://ttlc.intuit.com/community/system-requirements/help/minimum-system-requirements-for-turbotax-...
Options you have if you do not want to upgrade your OS :
1) use another company that still does support your old OS
2) use a local tax professional
3) use the ONLINE version instead
4) use the fill in forms on the IRS/state web sites and mail in the returns
5) buy a cheap windows PC.
