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Format new OWC Mercury Electra SSD; want to put High sierra on it.

Hello again. Had to be away for a while. I have CCC to copy El Capitan to my new SSD from my current one (SanDisk 256 GB)


I have an OWC Mercury Electra 1 TB I have it because I want to add some software that needs High Sierra, and a larger capacity to also run Elementary OS



So just to be clear I use Disk Utility to "Erase" the drive on the new SSD? Do I use "Journaled"? Extended Journaled? With GUID partition map, yes?


Then I copy to my new SSD using Carbon Copy Cloner, yes?


After that, is there any way I can get High Sierra? And if so, what do I need to do to put that on the new SSD? Can I download it, then use CCC to transfer that over to the new disk, then install it on the new SSD? Perhaps then boot from the drive to make sure that all is OK, then just install it in my MB Pro? (Mid 2010, core 2 duo, which Apple says will run High Sierra)


Please forgive all the questions; don't want to screw anything up, and don't do this every day :-)

Posted on Nov 20, 2021 10:47 AM

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Posted on Nov 20, 2021 7:33 PM

Yes you will need to erase the physical SSD as GUID partition and MacOS Extended (Journaled) before you can use the new SSD. Then you can use CCC to clone the drive. Then you will need to download the macOS 10.13 installer from a link within this Apple article which also contains optional instructions for creating a bootable macOS USB installer:

https://support.apple.com/en-us/HT201372


Another option would be to install macOS 10.13 to the new SSD, then migrate everything from the old drive. This option may be simpler, but if you have third party apps which require a license key, then using CCC may be the better option since Migration Assistant/Setup Assistant does not always transfer the license keys to the proprietary third party apps.


You can easily test the new SSD by booting it externally. Keep in mind if you decide to upgrade to macOS 10.13 with the new SSD connected externally, then you may need to Option Boot after the initial copy phase of the macOS install process finishes since many times the Mac will default to boot the original OS from the internal drive. No matter what you will need a working internal drive installed in order to install macOS 10.13 even when installing macOS 10.13 to an external drive.


Of course if your original drive is connected during the OS upgrade process, then there is always a risk you could upgrade the wrong drive by accident. Plus macOS may make some modifications to the recovery partition of the original drive when upgrading to macOS 10.13.


I suggest having a good backup before making any changes just to be safe. Also make sure the backup drive is physically disconnected from the laptop so the backup is not accidentally damaged.


You should always have frequent & regular backups.

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4 replies
Question marked as Top-ranking reply

Nov 20, 2021 7:33 PM in response to Knopflerfan

Yes you will need to erase the physical SSD as GUID partition and MacOS Extended (Journaled) before you can use the new SSD. Then you can use CCC to clone the drive. Then you will need to download the macOS 10.13 installer from a link within this Apple article which also contains optional instructions for creating a bootable macOS USB installer:

https://support.apple.com/en-us/HT201372


Another option would be to install macOS 10.13 to the new SSD, then migrate everything from the old drive. This option may be simpler, but if you have third party apps which require a license key, then using CCC may be the better option since Migration Assistant/Setup Assistant does not always transfer the license keys to the proprietary third party apps.


You can easily test the new SSD by booting it externally. Keep in mind if you decide to upgrade to macOS 10.13 with the new SSD connected externally, then you may need to Option Boot after the initial copy phase of the macOS install process finishes since many times the Mac will default to boot the original OS from the internal drive. No matter what you will need a working internal drive installed in order to install macOS 10.13 even when installing macOS 10.13 to an external drive.


Of course if your original drive is connected during the OS upgrade process, then there is always a risk you could upgrade the wrong drive by accident. Plus macOS may make some modifications to the recovery partition of the original drive when upgrading to macOS 10.13.


I suggest having a good backup before making any changes just to be safe. Also make sure the backup drive is physically disconnected from the laptop so the backup is not accidentally damaged.


You should always have frequent & regular backups.

Nov 23, 2021 2:59 AM in response to HWTech

Hi again -- got the new SSD formatted and copied everything over to it; with El Capitan. Was able to boot from the new SSD.


So now I have another question. Some other site made sure to format the disk in something called GPT or MBR, otherwise High Sierra might won't work on it. Are you familiar with this? Or can I just install the disk, download the link to HS, and let the installation go ahead? Not sure what these new file partitions are.


I don't need to first upgrade to Sierra first before going to HS, do I? Please forgive my questions, but I don't do this often :-)

Nov 23, 2021 5:01 AM in response to Knopflerfan

You want to erase macOS drives as GUID partition and MacOS Extended (Journaled). If you are installing macOS 10.13+, then the installer will automatically convert the volume to APFS. GPT is another way some people refer to a GUID partition. MBR is a legacy partition type used by Windows and is not useful on Macs today except perhaps on a USB stick formatted as FAT or exFAT. Also the MacOS Extended (Journaled) file system is also referred to as HFS+.

Format new OWC Mercury Electra SSD; want to put High sierra on it.

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