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Install macos on external disk - Need help please

Hi there!


I created a partition in my external usb 3 disk -using the GUID map-, to install Mac os 10.11. I downloaded the installer package from apple and tried several times, but but when I choose this disk as a destination it says:


"You can not install OS X on this disk. The OS X system is not installed"


Of course it's not installed! ... I am trying to install it. :(


I read a lot of threads and tutorials, but I don't find any clue about this problem.


I am running Mac OS 10.9.4 and I need to test this update first with my software apps to see how it works.


Thanks in advance!


David

Posted on May 19, 2020 9:32 AM

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Question marked as Best reply

Posted on May 19, 2020 10:52 AM

First of all have you prepared your external disk properly.

Open Disk Utility,

in the left hand side panel chose the external section

and the Disk not any indented Volume

Click Erase,

give the Disk a name,

Format: Mac OS Extended (Journaled)

Scheme: GUID Partition Map

click Erase

After your Disk has been reformatted it is now ready to receive the installation of an OS.


Try the installation again.


And just to ask did you go through the procedure to download InstallMacOSX.dmg

open it to InstallMacOSX.pkg.

Open that so you see an installation window, which does not install El Capitan

but creates Install OS X El Capitan.app to your Applications folder on your internal drive.

With Install OS X El Capitan.app in your Application folder you can use that to install

El Capitan.


The copy of the install app self deletes after installing El Capitan, so make sure you keep a copy of the InstallMacOSX.dmg

if you need it in future, or you could just make a copy of the Install OS X El Capitan.app prior to installing and moving it to

an external drive for safe keeping. It is also possible to create a bootable USB installer disk, using the Install OS X El Capitan.app

in the Applications folder, and the createinstallmedia command in the Terminal app. Read the instructions here,

How to create a bootable installer for macOS – Apple Support

Similar questions

5 replies
Question marked as Best reply

May 19, 2020 10:52 AM in response to gamuso

First of all have you prepared your external disk properly.

Open Disk Utility,

in the left hand side panel chose the external section

and the Disk not any indented Volume

Click Erase,

give the Disk a name,

Format: Mac OS Extended (Journaled)

Scheme: GUID Partition Map

click Erase

After your Disk has been reformatted it is now ready to receive the installation of an OS.


Try the installation again.


And just to ask did you go through the procedure to download InstallMacOSX.dmg

open it to InstallMacOSX.pkg.

Open that so you see an installation window, which does not install El Capitan

but creates Install OS X El Capitan.app to your Applications folder on your internal drive.

With Install OS X El Capitan.app in your Application folder you can use that to install

El Capitan.


The copy of the install app self deletes after installing El Capitan, so make sure you keep a copy of the InstallMacOSX.dmg

if you need it in future, or you could just make a copy of the Install OS X El Capitan.app prior to installing and moving it to

an external drive for safe keeping. It is also possible to create a bootable USB installer disk, using the Install OS X El Capitan.app

in the Applications folder, and the createinstallmedia command in the Terminal app. Read the instructions here,

How to create a bootable installer for macOS – Apple Support

May 19, 2020 4:37 PM in response to Eau Rouge

It worked! :)


But now every of my apps recognizes this OS as a new computer, and they ask to authorize again everything! ...isn't there a way that this new OS is recognized as my computer??


How should I proceed?


I don't want to deauthorize and authorize every application just to test them.


Is there a way to do this?

Install macos on external disk - Need help please

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