User profile for user: vrayneau
vrayneau Author
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Installing Mac OS El Capitan onto an external hard drive

I'm having trouble installing mac os on an external drive. When system restarts it reverts to internal hard drive and won't finish the installation

IMac Early 2009, install of Mac OS El Capitan from external drive onto another external drive

Earlier Mac models

Posted on Jun 11, 2023 2:49 AM

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User profile for user: HWTech
HWTech
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Posted on Jun 13, 2023 9:49 AM

Just Option Boot the iMac and select the external boot volume assuming the installation got that far without error. Sometimes a Mac just won't automatically boot to the external drive when moving to phase 2 of the installation process. Option Boot & selecting the external drive should allow you to continue with the macOS install on the external.

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User profile for user: HWTech
HWTech
Community+ 2026
User level: Level 9
73,010 points

Jun 13, 2023 9:49 AM in response to vrayneau

Just Option Boot the iMac and select the external boot volume assuming the installation got that far without error. Sometimes a Mac just won't automatically boot to the external drive when moving to phase 2 of the installation process. Option Boot & selecting the external drive should allow you to continue with the macOS install on the external.

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User profile for user: BDAqua
BDAqua
User level: Level 10
251,131 points

Jun 11, 2023 4:57 AM in response to vrayneau

Maybe try this...


Make an Intel Mac Boot Directly to Startup Manager…

https://osxdaily.com/2021/02/26/make-intel-mac-boot-startup-manager/#:~:text=As%20with%20all%20command%20line%20activity%2C%20start%20by,sudo%20you%E2%80%99ll%20have%20to%20enter%20the%20admin%20password.?msclkid=19cc70e0ab9d11ecb47c8ddb8bcaef0f

Make an Intel Mac Boot Directly to Startup Manager (osxdaily.com)

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Installing Mac OS El Capitan onto an external hard drive

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