If you encounter Error 606 in TurboTax even after entering the license code correctly, try restarting your computer and launching TurboTax again. Ensure that you’re using the correct installer for your version and that your internet connection is stable. Disable any antivirus software temporarily, as it may interfere with activation. Re-enter the license code carefully, avoiding space... https://install-turbo-tax.com/how-to-fix-turbotax-error-code-606/