Admittedly, I found an old version of MacOS Sierra on a torrent site (the official link for the old version did not work) but otherwise the process is the same.įor anybody else having this issue, here is a step by step guide. I created an bootable USB with an old version and overwrote the Contents folder with the one from a 'new' version of Sierra. Or Apple could just post a Sierra Installer, with a non-expired certificate, AND a working createinstallmedia command! So either use the date change trick, or if you happen to have the 'old' installer, that trick works, too (using createinstallmedia of old installer then replacing the installer app on the prepared USB drive) - I read on another forum that the old version of the Sierra Installer is available from the App Store if you previously got it from there (I didn't so I can't try that), otherwise, you have to already have the old installer. Plainly put, it's not straightforward to try to use an El Capitan or High Sierra-prepared USB drive, then replace the installer with the Sierra one.

I spent 3 hours diligently going through every file (hidden and not hidden) and modified many XML/plist files to match, even copied over boot.efi into the two places (pulled from the installer via Pacifist) and I get a kernel panic when I try to boot with the USB drive. I'd recommend a fast drive like a Samsung T5 or OWC Envoy or similar, otherwise it will take a long time to boot. You will need at least a 40GB USB drive to do this. More or less achieves the same thing as a fully bootable installer and also doesn't require an internet connection to install. You then boot from that drive, launch the Install macOS Sierra.app and then choose your desired target drive from that. What I created as a workaround, is a fully installed Sierra boot drive that then has the Install macOS Sierra.app in its Applications folder. It is not a problem with the volume you are specifying to create the bootable media. Instead, the error thrown should refer to the Install MacOS Sierra.app missing the correct file. The error about 'invalid mount point', is a bit of a misnomer.

The files that are missing from the Contents/SharedSupport may include the following. It does work to install the OS though if you already have a bootable machine. When you then run the installer the resulting Install macOS Sierra.app does not include the necessary files to make a bootable installer. As at early Novemebr 2019, the current InstallOS.dmg that you download to install Sierra has a problem.

Disk maker x high sierra