SOLVED (possibly) : I use Windows 10 x64, so on the TurboTax shortcut icon on my computer desktop I right clicked and chose the option to 'Troubleshoot Compatibility', and I chose to run the program as Administrator. That seems to have solved this, as a successful update ensued. Hopefully this is all that was the issue, as frustrating as it was to get to this solution. Perhaps Intuit / TurboTax should add this solution as something for people to try that have this same issue.
