There are a few ways to check the progress of a Mac transfer:
1. If you are using the Migration Assistant, you can click the "Show Details" button to see a detailed progress bar.
2. If you are using Time Machine, you can open the Time Machine preferences and click the "Options" button to see a detailed progress bar.
3. If you are using an external hard drive, you can open the Finder and click on the hard drive in the sidebar. The progress bar will be in the bottom left corner of the Finder window.