Install Sierra on machines that shipped with High Sierra

[caughtinfire]

Has anyone had any luck with this? We've got some brand new Macs that need to match the rest of our environment. So far you can't boot to a Sierra bootable installer, and trying to run an install with the new machine in target mode has resulted in either errors or the installer getting to the point of reboot and just not doing anything. Is this something that be be fixed by tagging the machines differently through DEP? Thoughts?

 

[flowrider]

You could always attach an external drive with Sierra installed on it and boot from that drive. Then you could use the external boot drive to install Sierra on the internal drive.

Or update all your machines to High Sierra!

Lou

 

[treekram]

If your new Mac's are models that were introduced this past June, you have to use the 12.6 installer. Anything earlier won't install because they pre-date the Mac models introduced in June. If this is the issue and you don't have a 12.6 installer, you can install Sierra using one of your older machines to an external disk and then update this disk to 12.6 and then see if you can boot your new Mac from your this HDD. If that works, you can try cloning the disk to the new Mac.

 

[jbarley]

You have not mentioned what models your existing or the new machine are so this is just a suggestion.
You might try booting the new machine from the HDD of the existing machine connected via Target-disk-mode.
This would be the quickest way of seeing if your new machines are even capable of running Sierra.

 

[Fishrrman]

Post 3 above is "the answer".

Use one of the slightly-older Macs that CAME WITH Low Sierra.
RE-download the Low Sierra installer on one of them (if you don't already have a copy of it).
Use that installer to install a fresh copy of Low Sierra on an EXTERNAL drive.
Take that drive and connect it to one of the NEW Macs (that came with High Sierra).
Will the external drive boot the new Mac?
If so, then you'll have to "clone over" the Low Sierra install to the new Mac, then try booting it that way. IF it boots, you're good to go.

IF it WILL NOT BOOT... then I guess you're stuck with High Sierra on those Macs...

 

[Tech198]

You could always attach an external drive with Sierra installed on it and boot from that drive. Then you could use the external boot drive to install Sierra on the internal drive.

Or update all your machines to High Sierra!

Lou

Macs are too new to run anything older.. I don't think you'd have any other option. even if it was installed on external drive first.

The problem is chipset is not included in Sierra, but is in High Sierra for the new Mac models... and since Apple makes the drivers AND the hardware, your stuck to what u get from the shops.

I'm not saying it won't be possible to install on on older machine to external and bring it over afterwards, but u may not be able to get to the login screen after u boot it on the newer mac.

 

[Riwam]

You could always attach an external drive with Sierra installed on it and boot from that drive. Then you could use the external boot drive to install Sierra on the internal drive.

Or update all your machines to High Sierra!

Lou

Lou I have just made a new thread in the Sierra section.
Exactly what you suggest here in this post is presently (for reasons I don't know) not possible any longer for me.
The option key does not show me any external Sierra clone (or even an older OS clone) to boot from it.
In the past I could boot ElCap or even Yosemite besides Sierra... but not now!
Since you have a lot of experience, maybe you can help me.
My clones are all USB drives, I have no firewire drive to test if that works.
Thank you in advance for any help!

 

[flowrider]

^^^^I'm assuming the external USB drive is plugged into a USB port of the Mac itself, not a USB PCIe card or USB hub. With the unit plugged in, what happens when you go into "System Preferences" and choose "Startup Disk"? Do you see it

 

[Zabanitu]

After a lot of trial and error It is possible for me to downgrade: I just did it on two iMacs 2017 that shipped with Mac OS high Sierra.

What I had to do was a bit complicated because you will need some older versions of mac OS.



1. First I booted the iMacs into target mode by holding "T" when booting.

2. I connected the iMacs with High Sierra in target mode to a machine that had Yosemite installed. (Because Yosemite is the last OS that had the old "Disk utility app")

3. On the Yosemite open the Disk Utility App and remove the partitions that were formatted in AFS (apple file system)

It should be two partitions.

4. Create a new partition.

5. Boot the iMac 2017 from a Sierra 11.12.6 install disk by holding the option key while booting and selecting the install drive.

6. Complete the installation.



Note: It had to be Yosemite to remove both the AFS partitions, higher OS'es were only able to remove one of them.

 

[chrfr]

Note: It had to be Yosemite to remove both the AFS partitions, higher OS'es were only able to remove one of them.

It's not necessary to use the Disk Utility from 10.10.5 (although that version is still probably easier to use than any of the newer ones.)
Choosing the option to erase the entire disk in the newer versions of Disk Utility will get rid of any remnants of APFS. Sometimes it's easier to format the disk as one of the Windows formats (FAT or exFAT) and GPT formatting as an interim step, then formatting back to Mac OS Extended Journaled and GUID.