Sorry your Mac is too old.
Mac System Requirements
https://ttlc.intuit.com/questions/1899173-minimum-system-requirements-for-turbotax-mac-software
You will have to get a refund for the Desktop program. Then you can use the Online web version. Or try to upgrade your Mac or find another computer to install it on. The CD has both Windows and Mac programs on it.
Contact Customer Service 5am-9pm Pacific time 7 days a week, https://support.turbotax.intuit.com/contact/
So, I'm quarenteed, what do I do. I can't return now, Will your online optiuon work?
Can I upload something, like last years, 2018, and upgrade online?
@paulsgroup I don't understand you. What are you trying to do? Install the 2019 program? Yes you can transfer 2018 from your computer into the 2019 online version. You need to have the .tax2018 file on your computer.
How to transfer into Turbo Tax Online