Download Windows Installer 4.5 (applies to Vista and XP SP3 only)
Downloading a new or updated copy of Windows Installer can be used to resolve certain installation issues on Windows Vista and Windows XP SP3.
For Windows 7 and later, the installer that came with your operating system is the latest version.
- Go to the Windows Installer 4.5 download page and click Install Instructions.
- Download and install the file that is appropriate for your operating system version and platform.
- Once that's finished, restart your computer and then try installing TurboTax again.
If the same problem persists after downloading the updated installer, try the steps in Microsoft Article ID 315346.