Install Disk Creator 1.5 is a free utility for Mac which, starting from the installation file of OS X 10.11.x El Capitan and subsequent operating system, allows you to create a bootable disk with the operating system, a useful support, for example, to install the operating system on a stick and use it in an emergency for recovering functionality or as a starting point to install the same system on multiple machines.
Actually, it is possible to create these supports with a Terminal command, but this application (download from here) simplifies the procedure by making it unnecessary to type commands. The target disk or USB key must be at least 8GB initialized as HFS +. The minimum requirement is OS X 10.7 or higher.
We remind you that MDS has also been updated recently, a similar utility (also free) but oriented to the deployment in the corporate environment.
At the end of the procedure performed by Install Disk Creator 1.5, the USB key is ready. To start from this, restart your computer leaving it in a USB port, hold down the Option (Alt) key and, when prompted, choose the key as the startup disk. USB charging may be slow and you need to be patient- timing depends on the speed of the external device.
Wait patiently for the operating system to load from the key and select “Install macOS Big Sur” with the mouse/trackpad. After a few minutes, the “macOS Recovery” screen will appear. Enter the password of the administrator user, click on “Next”, enter the password of the Administrator user- a window appears from which you can choose “Disk Utility”, initialize the internal HDD / SSD of the Mac, exit Disk Utility and start the clean installation of macOS Big Sur. Perhaps it is superfluous to mention this but obviously, the initialization destroys all data- if you have important data on disk, make a backup copy first.
