I have been able to enter a Schedule K-1 in TurboTax Home and Business for Mac and have not encountered this message.
See here for forms availability for TurboTax for Mac. Schedule K-1 shows as available.
If your program isn't updating, try these steps:
- Make sure you're running the program from the Applications folder, not from a mounted virtual drive or CD.
- Wireless connections can be problematic. We recommend updating over a wired, broadband connection.
- If you don't have access to broadband, try restarting your wireless router.
- Empty the Trash.
- Force the update to download and install.
- If you're still having problems, turn off your computer, then your router, and lastly your modem, in that order.
- Wait a minute or two, then turn your modem back on.
- Wait another minute, then turn your router back on.
- Once your router is back up, turn your computer back on and try updating again.
See this help article for more information.