I have downloaded macOS Mojave from some other website due to Mac App Store download problem. So now I have to boot the installation file, to do so the help box of the website says I have to press and hold Option key on system restart.
Does this action erase my whole mac hard disk?
Best Answer
No, holding option on restart simply lets you boot off a different device. It doesn't erase anything. But having said that, downloading MacOS updates from anywhere except Apple is very risky, and I wouldn't recommend it. Booting from a different device won't erase your hard disk, but running a rogue installer could.