Install macOS on External Hard Drive
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edpas
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Hi everyone,
I have a problem installing macOS Mojave on an external hard drive from my MacBook Air (which is running Catalina).
I followed this tutorial from the Apple website:
https://support.apple.com/fr-fr/HT201372
Everything went well until step 5 of "Using the bootable installer," when I try to install Mojave, my Mac offers 3 drives: Mac HD, Mac (data), and Install macOS Mojave (so my external drive). But that one is grayed out and I can't use it to install Mojave because it is "locked." How do I unlock it so that I can finally use Mojave on my Mac when I need it?
Thanks for your help.
I have a problem installing macOS Mojave on an external hard drive from my MacBook Air (which is running Catalina).
I followed this tutorial from the Apple website:
https://support.apple.com/fr-fr/HT201372
Everything went well until step 5 of "Using the bootable installer," when I try to install Mojave, my Mac offers 3 drives: Mac HD, Mac (data), and Install macOS Mojave (so my external drive). But that one is grayed out and I can't use it to install Mojave because it is "locked." How do I unlock it so that I can finally use Mojave on my Mac when I need it?
Thanks for your help.
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Hello,
You are trying to install the OS on the same disk where you created the installer! This is not possible. You cannot install OS X on a disk that has been used to boot the Mac from an installation OS using the procedure indicated by Apple.
The procedure indicated on the Apple page you are quoting is the procedure that allows you to create a USB installation key (or another installation medium like a hard drive, for example), and then start the Mac from this medium and finally install the OS on a different medium.
The installer that was created in this way on a given medium cannot install the OS on the same medium.
You must create the installer on a different medium than your external drive. A USB stick, for example, and then start the Mac from this stick (hold down the option key), and finally launch the installation on your external drive, which you will have taken care to format in Mac OS Extended with GUID partition scheme beforehand. If this external drive is actually an external SSD you will format it in APFS.
Best regards.
PS: hi dede ;)
Install macOS Mojave (so my external hard drive)
You are trying to install the OS on the same disk where you created the installer! This is not possible. You cannot install OS X on a disk that has been used to boot the Mac from an installation OS using the procedure indicated by Apple.
The procedure indicated on the Apple page you are quoting is the procedure that allows you to create a USB installation key (or another installation medium like a hard drive, for example), and then start the Mac from this medium and finally install the OS on a different medium.
The installer that was created in this way on a given medium cannot install the OS on the same medium.
You must create the installer on a different medium than your external drive. A USB stick, for example, and then start the Mac from this stick (hold down the option key), and finally launch the installation on your external drive, which you will have taken care to format in Mac OS Extended with GUID partition scheme beforehand. If this external drive is actually an external SSD you will format it in APFS.
Best regards.
PS: hi dede ;)
edpas
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Thank you so much for this clarification!! I've partitioned my hard drive and installed Mojave on this new partition! Everything is working wonderfully!! Thanks again!! :)
