I have exactly the same problem. Purchased Premier at a store. Tried to install but refused to run, because my Mac OS is 10.12.6 and Intuit wants me to install 10.13.6. Then tried to do this on the Apple store, but Apple let me not do this. I did find 10.13.6 , but when downloading it the message is that this file is corrupted. Clearly Apple want me to go to Catalina, but then many of my older applications will not work anymore. There was also a message then from Intuit that i Could try to download Premier from their web that then would work with 10.12.6, but I have not been able to find that on their site.
After so many hours wasted, I want a refund and will leave Turbotax after 20 more years (I started with MacIntax)
