That makes me think that there is an issue in the Applications Support folder where the form updates are stored. I suggest that a *total* uninstall of TurboTax and *all* of the support files and a re-install will solve this issue. This usually corrects issues such as yours. It is much easier to just uninstall everything that to try to trouble-shoot and isolate the problem to a particular file of preference file which could be very time consuming.
Corruption could have occurred in the Application or in an associated preference or support file. To uninstall the application and all associated files need to be deleted and then the application reinstalled. If there was a state then the state must also be reinstalled.
Here is a FAQ for how to uninstall Mac
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**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**