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Can't install older OS on partition

I have a partition and I am trying to install Sierra on it because I need to run software which needs Sierra. When I run the installer, it skips past the destination option and says it will install on Macintosh HD, which is the main HD and so would erase that, which I do not want!! It also says the install will take up 16.5 mb, which makes no sense. The partition is formatted as Mac OS journaled extended, which is what Sierra needs as it will not install on APFS. So why am I not getting an HD choice to install to the correct place? I didn't proceed past the screen pictured because I worried it might start installing on my main HD.

iMac Line (2012 and Later)

Posted on Apr 30, 2020 10:17 PM

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Posted on May 1, 2020 2:15 PM

Cartoonguy Said:

"It is mounted and accessible and reads and writes, but I can't get the OS to install on it."

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Installing This:

  • From a USB installer

Go Here: How to create a bootable installer for macOS - Apple Support.


  • Use Option-Command-R

How to reinstall macOS from macOS Recovery - being a new partition, as the site reads: If macOS Sierra 10.12.4 or later has never been installed on this Mac, Option-Command-R installs the macOS that came with your Mac, or the closest version still available. And Shift-Option-Command-R isn't available.


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9 replies
Question marked as Top-ranking reply

May 1, 2020 2:15 PM in response to Cartoonguy

Cartoonguy Said:

"It is mounted and accessible and reads and writes, but I can't get the OS to install on it."

-------


Installing This:

  • From a USB installer

Go Here: How to create a bootable installer for macOS - Apple Support.


  • Use Option-Command-R

How to reinstall macOS from macOS Recovery - being a new partition, as the site reads: If macOS Sierra 10.12.4 or later has never been installed on this Mac, Option-Command-R installs the macOS that came with your Mac, or the closest version still available. And Shift-Option-Command-R isn't available.


May 2, 2020 4:56 AM in response to Eau Rouge

Cartoonguy Said:

“Can't install older OS on partition: [...]The clue is that it says it will take 16.5MBs of space, no mac OS can only be 16.5MBs. The Install macOS Sierra.app is 5.05GBs[...]

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Thank you for the clarifications.


Please Report this File’s Bug to Apple:

Having troubleshot all of this, the last step here, so it seems, is a matter of feedback. I would report this bug in the update to Apple. Apple should definitely be made aware of an update reporting itself as about 3% of its actual size..

  1. Go Here: Feedback - macOS - Apple
  2. Select:Software/Hardware Compatibility” for the “Feedback Type
  3. Select:Software/Firmware Update” for the “Feedback Area
  4. Proceed from there as necessary

May 1, 2020 12:03 AM in response to Cartoonguy

Cartoonguy Said:

"Can't install older OS on partition: I have a partition and I am trying to install Sierra on it because I need to run software which needs Sierra. When I run the installer, it skips past the destination option and says it will install on Macintosh HD,[...]"

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Mount the Partition:

You've just created a partition for this, correct? If that is the case, mount it, doing so in Disk Utility, while booted in Recovery Mode. Having just been mounted, see if it now gives you the option to use it. If not, then while in Recovery Mode, run First Aid, and see if there is anything that needs to be fixed.


Mounting it Anew:

As a last resort, just delete this newly-created portion, and then create a new one, mounting afterwards, and then proceeding with the install.

May 2, 2020 1:35 AM in response to Cartoonguy

Oh well what you missed was that the Installation window you get does not install macOS Sierra but converts the InstallOS.pkg to the Install macOS Sierra.app which you find is created in the Applications folder. The clue is that it says it will take 16.5MBs of space, no mac OS can only be 16.5MBs. The Install macOS Sierra.app is 5.05GBs in size and you double-click on that to start the installation of macOS Sierra, follow the screen prompts and you will see one that asks you which Disk/ partition you want to install macOS Sierra. It's that simple.

May 2, 2020 12:27 PM in response to Cartoonguy

Just to summarize the solution, I had to go back by booting into Recovery using Shift + Option + CMD + R. That takes you to a version of Recovery which will go back and install the same OS the Mac came with at purchase. In my case, it was Mavericks, so I installed that to my 120GB SSD drive. In order to load the version of Final Cut Pro I needed in order to convert projects, I then had to upgrade to El Capitan, which I did. Then I installed the older FCPX which was the last version to convert the old file system to libraries, then I loaded the old projects and converted them. Job done, I then erased the partition and got rid of the OS and old FCPX. Now I have a blank 120 GB SSD to store stuff on. Long story, but in the end, it got done in a couple of hours, which was not too bad. Took longer to get all the info about how, so thanks to those who helped here.


P.S. My 120 GB SSD was formatted APFS, but to install and old OS, it needed to be erased and formatted as Mac OS Extended Journaled. Just wanted to add that in case anyone needs to do this.

Can't install older OS on partition

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