Cannot install Catalina on external SSD

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Level 1

5 points

Cannot install Catalina on external SSD

I'm trying to install Catalina to an external SSD, which worked before but not now. Installation files are put on the target disk, and Mac reboots, but to the login screen of the internal HD, and installation does not proceed.

How can I get the install to proceed?

SSD is formatted as HFS+. Mac is a 2014 iMac (model identifier14,4), with 10.11.6 on internal HD.

It has run on Catalina from the SSD, but there were glitches, and I decided to reinstall from scratch.

iMac Line (2012 and Later)

Posted on Oct 29, 2021 5:30 AM

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Answer 1

Eau Rouge

Level 8

42,656 points

Oct 29, 2021 5:47 AM in response to teobaldo

You should have the Install macOS Catalina.app on your macs internal drive.

Double-click on that to start the installation, follow the prompts.

A couple of screens in you should be asked which Disk you want to install

Catalina on, choose the external SSD, and proceed.

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Answer 2

teobaldo Author

Level 1

5 points

Oct 29, 2021 6:57 AM in response to Eau Rouge

Sorry, no. I did run the installer. Been dere, done dat for over 20 years.

But…

Apparently installer got confused by the presence of another external, bootable drive. After I disconnected that, and rebooted, the install finished normally. Weird, but voodoo.

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Cannot install Catalina on external SSD

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