If you need Windows, you'll be prompted to Download and Install Windows 10 OR Works with OS X, Windows 10, 8.1, and 7, Linux, Unix and macOS Server. macOS Sierra needs its own hard drive partition, a minimum of 10 GB of space is … If your computer already has macOS installed, Sierra Installer will update macOS normally, without deleting any of your apps or files.
It can be the same computer as the one mentioned in the previous point.
