Install mac os on an external SSD drive

Trying to make an external SSD drive my boot drive.

I downloaded the Installer.

When it asks for destination and I choose the (erased) SSD drive it says "OS X can't be installed. macOS isn't installed".

The current OS on the (crashed) internal hard drive is Catalina. The Installer is Mountain Lion (couldn't find a Catalina installer, figured I'd upgrade later).

I followed these instructions:

https://discussions.apple.com/docs/DOC-250003583

iMac 27″, macOS 10.15

Posted on Dec 11, 2021 4:52 PM

Similar questions

18 replies

Jack-19

Level 8

46,420 points

Dec 13, 2021 8:22 PM in response to crisnyc

crisnyc wrote:

Is there a new link for OS Catalina? That one is still dead.

Try it again. The issue should be fixed.

crisnyc Author

Level 1

9 points

Dec 23, 2021 6:59 PM in response to TimORourkie

All done, set up, and working. Thanks.

crisnyc Author

Level 1

9 points

Dec 12, 2021 12:47 PM in response to Jack-19

Hi Jack,

Thanks so much. This Forum has been so helpful over the past few weeks.

I will try again later with instructions in the link you gave.

This is the SSD:

https://smile.amazon.com/gp/product/B0874XWW23/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

This thread has been closed by the system or the community team. You may vote for any posts you find helpful, or search the Community for additional answers.

Install mac os on an external SSD drive

Welcome to Apple Support Community

A forum where Apple customers help each other with their products. Get started with your Apple Account.

Learn more Sign up