My friend got a new MacBook Pro from office, later on he resigned and in a hurry erased the "Macintosh HD", now we are trying to install Mojave using Bootable USB but it won't allow because "External Boot" is not allowed, also when we try to access "Startup Security Utility" it shows an error saying no administrator was found, so we can't enable "Allow booting from external media". Somehow online installation from recovery mode is also not working and throws 202 error at the end. Is there any luck?
I had a similar issue with my 2018 Mini: I had to delete the .AppleSetupDone file and run the "Welcome to Mac" routine, creating a new admin user there before I could alter SecureBoot, even though the disk had been imaged with an admin user.
Peter Thorn's answer here gets to the exact cause of the problem and provides the solution for a working Mac that has MacOS installed.
If you don't have MacOs installed, you could try booting it in Target Mode from another Mac, which I understand bypasses the Secure Boot! (Though if the drive is encrypted, you'll need the password, unless you're wiping it anyway.)
Alternatively, take it to an Apple Store. The SecureBoot settings can't be changed unless there is a valid admin user, so you can't boot to an external. Recovery is another option, but you say that's not working.
PS. I'd love to work somewhere where you get to keep your laptop when you resign!
I just came into the same situation. But I was lucky enough to workaround it last night. It took me 2 nights searching around to figure out what to do. Here's what you need:
*. A functioning Mac(Better without a T2 chip), mine is the 2014 Mac Mini.
*. An SSD for a fresh install.
*. Create a bootable macOS USB drive.
I will make it short. You could search for tutorials if you don't know what to do for a certain step.
- Plug in both SSD and bootable USB drive(with Mojave installer).
- Reboot your mac and press Command + R.
- Install a fresh Mojave on your SSD, and stop when you see the welcome screen where it asks you to select your country.
- Power off and unplug the SSD off your functioning Mac.
- Plug your SSD onto your MBP and turn it on.
- Press Command + R and enter the recovery mode.
- Disk Utilities -> Restore. Here select your SSD and it will copy your SSD's files onto your MBP. And then you can unplug your SSD.
You could try select your internal drive as start up disk but it doesn't let you to. So reboot your MBP. And press Command + R. In my case it failed to boot the macOS and it just reboot into the recovery mode again.
Select Install Mojave. After a couple of minutes, your screen turns black and it reboots.
- You will see the lovely Welcome screen again.
I had to boot into recovery mode and reinstall High Sierra (the initial shipped version of macOS). Installing HS gave an administrator account. With the administrator account I was able to allow booting from any external device and finally booted from mac USB stick macOS mojave. After that I could remove HS.
To my experience, it is a question of Secure Tokens, if it doesn't accept the admin even though it has the shipped (old) macOS installed from the recovery partition.
Even though you have created an admin account, you need it to have a Secure Token and update the preboot, for the recovery partition to accept it.
I did the following (when logged in as the local admin account) (both commands run in Terminal):
sysadminctl interactive -secureTokenOn [admin user shortname] -password -
(you will be asked to authenticate).
diskutil apfs updatePreboot /