Partition Mojave HD to run Sierra

Started 5 months ago | Discussions
silentstorm Senior Member • Posts: 1,485
My shot "in the dark"

After reading through the replies, here's my take.

If you already have a newer OS (Mojave) in the laptop, you can't install older OS versions, not even external.

If you are really desperate to get old OS back, bite the bullet. Make sure backup all data!

1) Put in the installer USB of Mojave and boot into this installer during restart/bootup.

2) Erase disk using the Disk Utility. Do disk partitioning from it, create 2 partitions capacity of your choice.

3) Mojave has an option to format in HFS+ or APFS. Choose HFS+ for 1st partition.

4) Exit installer and shut down.

5) Plug in Sierra installer USB and boot into it.

6) Follow through the installation guide and select the 1st HFS+ drive to install Sierra.

7) Installation completed. Shutdown. Plug in Mojave installer USB.

8) Bootup into this Mojave USB installer disk.

9) Follow the installation process until you need to select which drive to install into.

10) Choose the 2nd partition and format it in APFS. Then proceed on.

Now I don't know if using time machine is a good idea to clone onto the 2nd partition. But I HIGHLY RECOMMEND that you fresh/clean install everything into Mojave to avoid any possible corruption on the boot sector of the drive.

Good luck!

EDIT:

Like to add.  If after erasing & creating new partitions, the Sierra OS still prompts you the error of an older OS, this means the drive is not thoroughly cleaned/wiped.  You have to find a way to thoroughly wipe the drive in this case.

Remove the drive from the laptop. Put it in an ext enclosure. Borrow from a friend or neighbour Windows computer. Plug in and use DOS command to do a clean wipe via Diskpart.exe utility.

Yes.  This can be a hassle, but if you need it, just do it.

silentstorm Senior Member • Posts: 1,485
2 things come to my head

Tom_N wrote:

Is there some reason that you can't install High Sierra?

Maybe OP needs to use 1) FCP 7 and 2) Telnet client

Hi Sierra has Telnet client removed and, cannot install FCP7.

Also, Apple's philosophy is always going forward.  You cannot install an older OS once a newer version is there.  Not even onto external drive. Especially true if the hardware comes with the newer OS, the firmware in the hardware will block any OSes that are older than the shipped version.

However you can install newer version OS onto external drive via the older OS.  Just not the other way round.

I know all these from past experience using a Lion OS machine, cracking my head night and day trying to install Snow Leopard back.

silentstorm Senior Member • Posts: 1,485
Easiest method

If your laptop is really the old 17", just removed the drive and buy a new SSD SATA drive.

Put in the new SSD drive and plug in the Sierra installer USB.  Install should be a breeze from here.

Get an external enclosure for the Mojave drive.  Use it as an external boot drive if u need to use Mojave OS.

This is by far the simplest and easiest method for getting back Sierra OS & no need to reinstall everything again in Mojave.

JohnNewman
OP JohnNewman Contributing Member • Posts: 942
Re: Easiest method

silentstorm wrote:

If your laptop is really the old 17", just removed the drive and buy a new SSD SATA drive.

Put in the new SSD drive and plug in the Sierra installer USB. Install should be a breeze from here.

Get an external enclosure for the Mojave drive. Use it as an external boot drive if u need to use Mojave OS.

This is by far the simplest and easiest method for getting back Sierra OS & no need to reinstall everything again in Mojave.

Thanks for your input. I’m fine with Mojave for just about everything apart from this one application that is actually on the 17”‘s HD. So could I remove this HD from the old machine as you suggest, put in an external enclosure and boot my MacBook Air from there if it was connected by USB?

If that worked I could carry on using my MBAir as normal and just attach the old (enclosed) HD when needed?

Thanks again,

John

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silentstorm Senior Member • Posts: 1,485
Re: Easiest method

JohnNewman wrote:

silentstorm wrote:

If your laptop is really the old 17", just removed the drive and buy a new SSD SATA drive.

Put in the new SSD drive and plug in the Sierra installer USB. Install should be a breeze from here.

Get an external enclosure for the Mojave drive. Use it as an external boot drive if u need to use Mojave OS.

This is by far the simplest and easiest method for getting back Sierra OS & no need to reinstall everything again in Mojave.

Thanks for your input. I’m fine with Mojave for just about everything apart from this one application that is actually on the 17”‘s HD. So could I remove this HD from the old machine as you suggest, put in an external enclosure and boot my MacBook Air from there if it was connected by USB?

If that worked I could carry on using my MBAir as normal and just attach the old (enclosed) HD when needed?

Thanks again,

John

If the Air is running Mojave, I don't think it will boot into Sierra external.  You can try that though.  If the Air has a physical drive and not soldered type, you could remove it and use it as an external Mojave drive on your old 17" Sierra laptop.

Tom_N Forum Pro • Posts: 19,349
Re: Easiest method

Here are two articles that might be of interest.

MacWorld UK – How to dual-boot Mac: run two versions of macOS on a Mac

MacWorld UK – How to downgrade macOS Big Sur to Catalina or older

"Regret upgrading to the new macOS? Here's how to revert from Catalina to Mojave, or Mojave back to High Sierra, or even back to Sierra or older. You can go back to the old macOS!"

It sounds like things do get more involved if you are (a) trying to downgrade, (b) trying to downgrade to Sierra or earlier, and (c) trying to put the older OS on a HFS+ volume.

JPAlbert Senior Member • Posts: 1,101
Re: 2 things come to my head
4

silentstorm wrote:
"You cannot install an older OS once a newer version is there. Not even onto external drive. "

This is absolutely, positively UNTRUE and is misinformation.

You CAN install an older version of the OS on a Mac, so long as it shipped with that version of the OS.

This is the reason that Apple offers a "special version" of internet recovery, accessed through "command-OPTION-SHIFT-R" at boot.
When you boot to this version of internet recovery, and it will download and install the ORIGINAL OS that shipped with the Mac you're using (or the current iteration of that particular OS). You DO have to completely erase the drive in the Mac beforehand to reinstall on the internal drive.

I just checked this with the 2015 MacBook Pro I'm holding in my hands and typing on right now. This MBP shipped with OS 10.11 El Capitan, but is now running OS 10.12 "Low" Sierra.

The steps I took:
1. Booted with the Command-OPTION-SHIFT-R key combo into special internet recovery (it takes a while).
2. I plugged in an SD card I had (which was already formatted to HFS+) and let its icon mount on the desktop.
3. Internet recovery presented the "OS utilities" to me.
4. I choose "reinstall OS X"
5. I plugged in an SD card I had (which was already formatted to HFS+)
6. The OS installer opened -- Install El Capitan.
7. I began clicking through, and selected the SD card as the target (which would be "an external drive")
8. The OS install actually began, but at that point I pressed and held the power button to cut off power. But again, the OS install had begun.

Again... you CAN install older versions of the OS onto any Mac which was originally capable of RUNNING those versions of the OS.

Tom_N Forum Pro • Posts: 19,349
Re: 2 things come to my head
1

JPAlbert wrote:

silentstorm wrote:
"You cannot install an older OS once a newer version is there. Not even onto external drive. "

This is absolutely, positively UNTRUE and is misinformation.

You CAN install an older version of the OS on a Mac, so long as it shipped with that version of the OS.

This is the reason that Apple offers a "special version" of internet recovery, accessed through "command-OPTION-SHIFT-R" at boot.
When you boot to this version of internet recovery, and it will download and install the ORIGINAL OS that shipped with the Mac you're using (or the current iteration of that particular OS). You DO have to completely erase the drive in the Mac beforehand to reinstall on the internal drive.

Right.  You can't install an older OS (that was originally supported on your model of Mac) over an old OS, but you can do a clean install on a freshly-reformatted drive/volume.

If you are going from a modern version of macOS that supports and prefers APFS, to an older version of macOS that does not know how to handle APFS, you probably will also need to redo the formatting on the target drive to use HFS+ (Mac OS X Extended) rather than APFS.

Even if you are going from a modern version of macOS to an earlier one that supports APFS, you may want to redo the formatting on the target drive.  APFS is a work in progress and some of the older implementations may not understand all of the options that APFS filesystems created using newer versions of macOS use.

I just checked this with the 2015 MacBook Pro I'm holding in my hands and typing on right now. This MBP shipped with OS 10.11 El Capitan, but is now running OS 10.12 "Low" Sierra.

The steps I took:
1. Booted with the Command-OPTION-SHIFT-R key combo into special internet recovery (it takes a while).

It sounds like knowing to use the "special" Internet Recovery system instead of the "usual" one may be an underappreciated key to getting things to work.  Good tip.

silentstorm Senior Member • Posts: 1,485
Re: 2 things come to my head

JPAlbert wrote:

silentstorm wrote:
"You cannot install an older OS once a newer version is there. Not even onto external drive. "

This is absolutely, positively UNTRUE and is misinformation.

You CAN install an older version of the OS on a Mac, so long as it shipped with that version of the OS.

This is the reason that Apple offers a "special version" of internet recovery, accessed through "command-OPTION-SHIFT-R" at boot.
When you boot to this version of internet recovery, and it will download and install the ORIGINAL OS that shipped with the Mac you're using (or the current iteration of that particular OS). You DO have to completely erase the drive in the Mac beforehand to reinstall on the internal drive.

I just checked this with the 2015 MacBook Pro I'm holding in my hands and typing on right now. This MBP shipped with OS 10.11 El Capitan, but is now running OS 10.12 "Low" Sierra.

The steps I took:
1. Booted with the Command-OPTION-SHIFT-R key combo into special internet recovery (it takes a while).
2. I plugged in an SD card I had (which was already formatted to HFS+) and let its icon mount on the desktop.
3. Internet recovery presented the "OS utilities" to me.
4. I choose "reinstall OS X"
5. I plugged in an SD card I had (which was already formatted to HFS+)
6. The OS installer opened -- Install El Capitan.
7. I began clicking through, and selected the SD card as the target (which would be "an external drive")
8. The OS install actually began, but at that point I pressed and held the power button to cut off power. But again, the OS install had begun.

Again... you CAN install older versions of the OS onto any Mac which was originally capable of RUNNING those versions of the OS.

Oh please Albert. Read my reply again.

For convenience... here is the part again "Especially true if the hardware comes with the newer OS, the firmware in the hardware will block any OSes that are older than the shipped version."

What you said is going back to the original OS that shipped with the hardware. You can't go back older than the shipped version.

If OP MBAir comes with Sierra, then yes, he can reformat his drive and get back the original OS. But if it comes with Mojave, then there's no way he could run Sierra on it, the firmware will block out Sierra.

EDIT:

I just checked, OP MBA laptop is a 2017 model.  If it comes installed with Hi Sierra (original shipped OS), then he can't go to Sierra at all.

Tom_N Forum Pro • Posts: 19,349
Re: 2 things come to my head

silentstorm wrote:

JPAlbert wrote:

Again... you CAN install older versions of the OS onto any Mac which was originally capable of RUNNING those versions of the OS.

Oh please Albert. Read my reply again.

For convenience... here is the part again "Especially true if the hardware comes with the newer OS, the firmware in the hardware will block any OSes that are older than the shipped version."

What you said is going back to the original OS that shipped with the hardware. You can't go back older than the shipped version.

If OP MBAir comes with Sierra, then yes, he can reformat his drive and get back the original OS. But if it comes with Mojave, then there's no way he could run Sierra on it, the firmware will block out Sierra.

EDIT:

I just checked, OP MBA laptop is a 2017 model. If it comes installed with Hi Sierra (original shipped OS), then he can't go to Sierra at all.

According to MacTracker, the MacBook Air (13-inch, 2017) originally shipped with macOS 10.12.4, which is a point release of SIerra.

During its retail lifetime (June 2017 to June 2019),  High Sierra came out (September 2017).  Apple would have started pre-installing High Sierra on new MacBook Air (13-inch, 2017) machines, starting then.  However, since the hardware model stayed the same, I don't know if Apple would have actively blocked the installation of Sierra (10.12.4 or later) on a MacBook (13-inch, 2017) that came preloaded with High Sierra and the High Sierra Recovery manager.

silentstorm Senior Member • Posts: 1,485
Re: 2 things come to my head

Tom_N wrote:

According to MacTracker, the MacBook Air (13-inch, 2017) originally shipped with macOS 10.12.4, which is a point release of SIerra.

During its retail lifetime (June 2017 to June 2019), High Sierra came out (September 2017). Apple would have started pre-installing High Sierra on new MacBook Air (13-inch, 2017) machines, starting then. However, since the hardware model stayed the same, I don't know if Apple would have actively blocked the installation of Sierra (10.12.4 or later) on a MacBook (13-inch, 2017) that came preloaded with High Sierra and the High Sierra Recovery manager.

When was the Air bought?  This question only OP can answer, and I wish him luck.  Hopefully was before Hi Sierra released.

ChrisLumix Veteran Member • Posts: 3,370
Re: 2 things come to my head

silentstorm wrote:

JPAlbert wrote:

silentstorm wrote:
"You cannot install an older OS once a newer version is there. Not even onto external drive. "

This is absolutely, positively UNTRUE and is misinformation.

You CAN install an older version of the OS on a Mac, so long as it shipped with that version of the OS.

This is the reason that Apple offers a "special version" of internet recovery, accessed through "command-OPTION-SHIFT-R" at boot.
When you boot to this version of internet recovery, and it will download and install the ORIGINAL OS that shipped with the Mac you're using (or the current iteration of that particular OS). You DO have to completely erase the drive in the Mac beforehand to reinstall on the internal drive.

I just checked this with the 2015 MacBook Pro I'm holding in my hands and typing on right now. This MBP shipped with OS 10.11 El Capitan, but is now running OS 10.12 "Low" Sierra.

The steps I took:
1. Booted with the Command-OPTION-SHIFT-R key combo into special internet recovery (it takes a while).
2. I plugged in an SD card I had (which was already formatted to HFS+) and let its icon mount on the desktop.
3. Internet recovery presented the "OS utilities" to me.
4. I choose "reinstall OS X"
5. I plugged in an SD card I had (which was already formatted to HFS+)
6. The OS installer opened -- Install El Capitan.
7. I began clicking through, and selected the SD card as the target (which would be "an external drive")
8. The OS install actually began, but at that point I pressed and held the power button to cut off power. But again, the OS install had begun.

Again... you CAN install older versions of the OS onto any Mac which was originally capable of RUNNING those versions of the OS.

Oh please Albert. Read my reply again.

For convenience... here is the part again

"Especially true if the hardware comes with the newer OS, the firmware in the hardware will block any OSes that are older than the shipped version."

What you said is going back to the original OS that shipped with the hardware. You can't go back older than the shipped version.

If OP MBAir comes with Sierra, then yes, he can reformat his drive and get back the original OS. But if it comes with Mojave, then there's no way he could run Sierra on it, the firmware will block out Sierra.

EDIT:

I just checked, OP MBA laptop is a 2017 model. If it comes installed with Hi Sierra (original shipped OS), then he can't go to Sierra at all.

That's only partly true. My original 2011 iMac shipped with Lion. The supplier was able to erase and reformat the HD and install Snow Leopard on it. That model (not that machine) originally came with Snow Leopard, though later sales were shipped with Lion.

So the "shipping" point is not as moot as which particular OS the model in question FIRST SHIPPED WITH. Later examples may ship with a later OS but that doesn't mean the original OS for that model can't be installed.

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Panas0n!c Lum!x LX100, TZ60

silentstorm Senior Member • Posts: 1,485
Re: 2 things come to my head

ChrisLumix wrote:

"Especially true if the hardware comes with the newer OS, the firmware in the hardware will block any OSes that are older than the shipped version."

What you said is going back to the original OS that shipped with the hardware. You can't go back older than the shipped version.

If OP MBAir comes with Sierra, then yes, he can reformat his drive and get back the original OS. But if it comes with Mojave, then there's no way he could run Sierra on it, the firmware will block out Sierra.

EDIT:

I just checked, OP MBA laptop is a 2017 model. If it comes installed with Hi Sierra (original shipped OS), then he can't go to Sierra at all.

That's only partly true. My original 2011 iMac shipped with Lion. The supplier was able to erase and reformat the HD and install Snow Leopard on it. That model (not that machine) originally came with Snow Leopard, though later sales were shipped with Lion.

So the "shipping" point is not as moot as which particular OS the model in question FIRST SHIPPED WITH. Later examples may ship with a later OS but that doesn't mean the original OS for that model can't be installed.

No. It is very true. What you and Albert experienced is timeline down the road OS updated, and considered going back to original OS as older OS. Your supplier updated older machine to Lion and sold it to you. You as the customer perceived it as default OS from the shipped machine, but in actual fact it was updated w/o your knowledge.

My Air was bought on 1 week Aug 2011, and was shipped with Lion (end July 2011 released). I cannot get it back to SL. The firmware blocked everything.

For OP case, if his Air came with Sierra, or similar to your case the Air was updated to Hi Sierra from an older machine before shipped, he can go back to original shipped OS. If his Air was bought later in Nov 2017, he can't go back any older than Hi Sierra. For us to know what is what, OP need to test it out himself to see if a wiped drive can install Sierra.  All we can do here is speculate over his situation.  Hopefully he would update us on his progress.

Coming back to the timeline, if anyone were to buy a new apple computer today shipped with Big Sur, what would you consider as older OS?  Big Sur? Since Monterey was already announced?

ChrisLumix Veteran Member • Posts: 3,370
Re: 2 things come to my head

silentstorm wrote:

ChrisLumix wrote:

"Especially true if the hardware comes with the newer OS, the firmware in the hardware will block any OSes that are older than the shipped version."

What you said is going back to the original OS that shipped with the hardware. You can't go back older than the shipped version.

If OP MBAir comes with Sierra, then yes, he can reformat his drive and get back the original OS. But if it comes with Mojave, then there's no way he could run Sierra on it, the firmware will block out Sierra.

EDIT:

I just checked, OP MBA laptop is a 2017 model. If it comes installed with Hi Sierra (original shipped OS), then he can't go to Sierra at all.

That's only partly true. My original 2011 iMac shipped with Lion. The supplier was able to erase and reformat the HD and install Snow Leopard on it. That model (not that machine) originally came with Snow Leopard, though later sales were shipped with Lion.

So the "shipping" point is not as moot as which particular OS the model in question FIRST SHIPPED WITH. Later examples may ship with a later OS but that doesn't mean the original OS for that model can't be installed.

No. It is very true. What you and Albert experienced is timeline down the road OS updated, and considered going back to original OS as older OS. Your supplier updated older machine to Lion and sold it to you. You as the customer perceived it as default OS from the shipped machine, but in actual fact it was updated w/o your knowledge.

My Air was bought on 1 week Aug 2011, and was shipped with Lion (end July 2011 released). I cannot get it back to SL. The firmware blocked everything.

For OP case, if his Air came with Sierra, or similar to your case the Air was updated to Hi Sierra from an older machine before shipped, he can go back to original shipped OS. If his Air was bought later in Nov 2017, he can't go back any older than Hi Sierra. For us to know what is what, OP need to test it out himself to see if a wiped drive can install Sierra. All we can do here is speculate over his situation. Hopefully he would update us on his progress.

Coming back to the timeline, if anyone were to buy a new apple computer today shipped with Big Sur, what would you consider as older OS? Big Sur? Since Monterey was already announced?

Yes, you must be right. My 2011 iMac came with 10.6.6 originally - when I got hold of the 10.6.3 DVD, which was the last 10.6 disk issued - it wouldn't install it onto an external HD . I'd forgotten about that, but there was some trick that let me do it in the end, though I can't now remember what that was.

(Ah, my filing system came to the rescue - here's what I had to do!):

• Use Disk Utility to make a read/write DMG of a 10.6.7 install disk for a MacBook Pro or iMac.
• Insert a 10.6.0 or 10.6.3 OSX retail installation disk in your DVD drive and use the Finder to open the disk to system/Installation/Packages/
⁃ open a Finder window of the 10.6/10.63 Installer disk, then press Shift-Cmd-G - in the popup type
⁃ System/Installation/Packages (no trailing "/") and press return, it will show the content of that hidden folder.
⁃ You will have to do this again, in another window, for the 10.6.7 Installer disk.
• One of these package files is OSInstall.mpkg which is the set of instructions for the Installer. This file in the 10.6.7 Installer is where the checking is done to see if it's installing to the 'correct' computer.
• Open another Finder window, and navigate to the same place in the 10.6.7 Installer. Replace the existing OSInstall.mpkg file with the one from the retail disk plus copy over all the printer related Installer packages. We do this because the retail installation script won't install the 10.6.7 printer packages. Check the 'copy all' box when the Finder warns you that the files already exist.
• Open Disk Utility and plug in an 8 gig thumb drive. Find the drive on the left side of the Disk Utility window and click on it. Now click Partition, chose 1 Partition, give it a name and click the Options button. Choose the GUID partition choice and close the window. Click the Partition button. When the Disk Utility is done, use SuperDuper or Carbon Copy Cloner to clone the modified 10.6.7 Installer to the 8 gig keychain drive. I had problems getting the Backup utility in Disk Utility to do this. You can boot any ready for Snow Leopard Mac with this Installer..

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Panas0n!c Lum!x LX100, TZ60

Tom_N Forum Pro • Posts: 19,349
Re: 2 things come to my head

silentstorm wrote:

Coming back to the timeline, if anyone were to buy a new apple computer today shipped with Big Sur, what would you consider as older OS? Big Sur? Since Monterey was already announced?

Some of the Intel-based Macs in the current lineup originally shipped with older OSes.  E.g., current Intel-based Minis date from 2018, and originally shipped with Mojave.

All of the M1-based Macs started with some version of Big Sur, and cannot go back to earlier OSes.

silentstorm Senior Member • Posts: 1,485
Re: 2 things come to my head

Tom_N wrote:

silentstorm wrote:

Coming back to the timeline, if anyone were to buy a new apple computer today shipped with Big Sur, what would you consider as older OS? Big Sur? Since Monterey was already announced?

Some of the Intel-based Macs in the current lineup originally shipped with older OSes. E.g., current Intel-based Minis date from 2018, and originally shipped with Mojave.

All of the M1-based Macs started with some version of Big Sur, and cannot go back to earlier OSes.

I'm not sure about the current intel mini (brand new) if they are firmware locked, but those under refurb certainly can go back to original shipped OS. I know cos' I have a 2015 MBP refurb and can install El Cap.

To the knowing: "OK~ I can zap this back to Mojave"

To the unknowing: "Oh WOW! I can go back to older OS, this is a miracle from apple!"

Depends which side you are on, the perspective is different, but the fact remains unchanged.

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