Please contact Turbo Tax customer support, please this TurboTax FAQ: 

https://ttlc.intuit.com/replies/3300041

1)  Restart the Mac

2) if it persists then:

Corruption could have occurred in the Application or in an associated preference or support file.

The best remedy is to totally uninstall TurboTax and all associate files and then re-install. That will not delete or change any .tax2019 data file that had already been created with the tax data.

To uninstall the application and all associated files need to be deleted and then the application reinstalled. If there was a state then the state must also be reinstalled.

Here is a FAQ for how to uninstall Mac
https://ttlc.intuit.com/questions/1901210-remove-uninstall-turbotax-for-mac

https://ttlc.intuit.com/questions/1901209-reinstall-turbotax-mac

Thanks - I did this on two different Mac laptops and I am still getting the same problem.  I spent 2 hours on Saturday with support to no avail.  Will try support again today.  Note that I wasn't able to delete the Turbo tax 2019 binary cookie as listed in the link (even as root).  I am stuck in a loop where the application starts to load - does a check for latest update and then stops loading.

That's odd.  That would seem to indicate that there is some sort of  permission issue with that file or the folder that it is in.   If your user account is a system administrator then you should have rw permission on the file and should be able to trash it.  There should be not file in you own user Library that you cannot delete.

Is there any message when you drag it to the trash?  

If after deleting all the files can you download a fresh copy of the TurboTax .dmg file and reinstall that (without state) and open that?   Perhaps there is a problem with that particular state file but if you delete the Application Support files then that should remove the state so the TT application should run if installed without the state (you will not be able to open your .tax2019 file without the state but should be able to start a new tax return  as a test).

Be sure to clear the trash and restart the Mac after doing the uninstall before re-installing.