I have the exact same issue. Purchased TurboTax Deluxe 2020 CD from Costco. When my son tried to download on his laptop using my license code (as he has no CD drive), it gives the error "This license code is associated with an account". This error message pops up even if he logs into my account and tries to download.
Looks like several people have the same issue.
I have been on their support line for over 30 minutes now.
