Need to stop for today, but do not wish to loose my work. I using a Mac.

[Sargeant · Accepted solution]

If you're online:

Go to My Account, then go to Save & Sign Out. Your progress will be saved.

If you're using the Desktop version:

Go to File on the upper left and click on "Save tax return", that will save your taxfile. When you open up your TurboTax program, you will then go back to File, click on "Open tax return" and look for your taxfile.