You can transfer your prior year returns prepared in the Windows version into your current year TurboTax online return. You'll just need to find those files on your Windows computer (example *.TT20 files) and copy them somewhere on your Mac. Then, when TurboTax online asks you if you want to transfer from a prior year, browse to those *.TT20 files to import them.
For more information, please see:
What are the options for using TurboTax on a Mac computer?
What can I do if I purchased TurboTax as a download or on a CD, but I have a Mac computer?
Thank you for choosing TurboTax. If you have further questions, please feel free to contact us