Here is what worked for me on Windows 10:
- Close TurboTax 2019 if open;
- Open File Explorer and navigate to the following folder:
C:\Users\<your user name>\AppData\Roaming\Intuit\TurboTax
- Delete or rename (just in case) TY19 folder under it to anything you want as it will be recreated on next TurboTax 2019 start;
- Start TurboTax 2019;
- Input License Code when prompted and click Activate Now.
It should work.
It appears that the configuration/database that are stored in that folder are getting corrupted or become incompatible (perhaps due to entity changes) after certain updates. Maybe this folder needs to be always regenerated upon update?
