Contains operating systems downloaded from Apple :

- 10.15 Catalina


To install the operating system, proceed as follows :

  1. Shut down or turn off your Mac.

  2. Connect the bootable installer directly to your Mac.

  3. Turn on your Mac, then immediately press and hold the Option (Alt) key.

  4. Release the Option key when you see a dark screen showing your bootable volumes, including the bootable installer.

  5. Select the bootable installer, then click the onscreen arrow or press Return.