The mac version will check for updates every time you start the program unless your internet is turned off. So you can bypass the problem by unplugging your wire or turning off your Wi-Fi.
I'd rather see the problem fixed. Try these instructions to remove all parts of turbotax including hidden files, then re-install from CD or a fresh download, install your state, then check for updates.
Also, before doing that, you may want to open Disk Utility and run a first aid check on your hard drive and a repair permissions if your version of the Mac OS still has that function.
Uninstall mac https://ttlc.intuit.com/questions/1901210-remove-uninstall-turbotax-for-mac