You did not mention which program you are using but I suspect it is the downloaded version and you need to do a program update.
I am using the Deluxe version and when I started this AM it updated and since I have checked for updates to no avail?
TurboTax for Mac automatically adds the current tax form updates whenever you select Check for Updates from the TurboTax menu. This creates the illusion that updates are available even if you're on the latest release.
If you want to make sure you're up-to-date, quit and reopen TurboTax. If you're not on the latest release, the program will automatically download it.
Other OptionsIf the steps above don't work, you can force a download of the most recent update. This applies to TurboTax for Mac installed from a CD or download and for the TurboTax 2018 app available in iTunes.
1. With TurboTax open, select the TurboTax menu.
2. On your keyboard, hold down the Option key.
3. This will change the Check for Updates menu option to Download Latest Updates...
4. Selecting this option will force the most recent update for TurboTax to download and install.