You can not use the PDF file. You need to have the data file ending in .tax2015. The .tax file can be read on both Windand Mac computers. If you don't have the .tax file you will have to recreate the 2015 return exactly as filed. Then when it matches each line on your return you can amend it.
Do you still have the Windows pc? Search for all files ending in .tax. And check the Recycle Bin. It should be in your Documents then in a Turbo Tax subfolder.
