Yeah I had the same problem, the following should solve the problem.
Go to your System Preferences, located in your Applications Folder, open it select (Security & Privacy) Click on the General Tab. Change (Allow apps downloaded from) to (Anywhere). You may have to Click on the Padlock and enter your admin password. Then Start Turbotax allow TurboTax to update. Then after Turbotax has run once you can change the (Allow apps download from) setting back to the more secure default setting to (Mac App store and Identified Developers),
Hope this helps.
