This error can occur when the Microsoft .NET Framework Installer can't install and/or update your system. Possible causes include:
- Damaged Windows file and folder permissions
- Damaged Windows Registry key permissions
- Damaged Microsoft .NET Framework installation
Please click this TurboTax Help link to learn how to fix it.
https://ttlc.intuit.com/community/bugs-and-error-messages/help/error-1603-a-fatal-error-occurred-during-installation-or-updating/00/26193