bootable usb mac os sierra new ssd not showing

It would be helpful to have confirmation of what exact Mac model you are trying to do this on, as an example no Mac Pro desktop computer enforces secure boot. In this case you need to boot from Internet Recovery. If however you have erased the Mac so it has no OS then this will have erased the RecoveryHD volume as well. MacBook Pro Mid 2018 or MacBook Air Late 2018 which comes with a copy of the macOS already installed. The process listed by BDAqua would be correct for a new e.g.

To resolve this issue I used recovery mode where in the Utility option I tried to change but to do this an admin account and password is required. And when I am trying to install macOS from the external media a error message appeared ' Security settings do not allow this mac to use an external startup disk'.

But here in my case my macbook doesn't have any OS. Thanks for reply but the process you have shared this process applies when mac has an OS already. When I reinstalled macOS, I got an error saying 'Couldn't create preboot volume for APFS' if you encounter a similar error you can reply to this post. With 150 Mbps of internet speed mine took about half an hour. The installation of macOS High Sierra is highly dependant on your internet speed. After completing the basic formalities of agreeing to the terms and conditions, installation of macOS High Sierra will begin.Clicking this should take you to a screen where you chose the disk you would like to install macOS High Sierra on.

After the internet recovery mode is all loaded up, click on the reinstall macOS High Sierra.This will get you into internet recovery mode, which should be a grey logo of a globe.As soon as the MacBook Pro is on and the background sound is heard, hold down the Command (⌘) – Option (⌥) – R combination of keys.Power off your MacBook Pro and then power it on.Ensure your MacBook Pro is connected to a reliable wifi source that can hold up for about an hour.You can solve the absence of having an OS on your Mac by following the following steps. Having a running OS off of an external drive is not usually recommended, so I strongly advice against it.

Bootable usb mac os sierra new ssd not showing