Error 1719: Windows Installer service could not be accessed occurs when updating TurboTax.
Solution
If you're using Windows 10, try this solution:
If you're using XP or Vista, download the Windows Installer.
If you're using Windows 7 or later (or downloading the Windows installer didn't work for XP/Vista), here are 3 more potential solutions:
Run the Windows System File Checker, then try updating again.
Re-register the Windows Installer: Click Start > Run > type MSIEXEC /UNREGISTER > click OK (it'll look like nothing happened). Then do the same thing except this time type MSIEXEC /REGSERVER. Now try updating again.
Start the Windows Installer Service: