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Tough question regarding using MacOS from an External Drive.

I'm with an 2019 iMac. Going to add an External Drive to replace the internal present drive.

( I want a Clean / Like new macOS on the external Drive)

Instead of using Migration Assistant , Is it possible to "see" Both internal (Old) drive AND the (New) external drive in parallel ?

So after installing the macOS on the external (New) drive , I will MANUELLY transfer what I want to the new drive.

Thanks

PS. I'm using iCloud Drive.


iMac 21.5″

Posted on Oct 28, 2023 6:11 AM

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Question marked as Top-ranking reply

Posted on Oct 28, 2023 6:58 AM

I did this with a 2017 iMac to speed up everything with an external SSD connected via USB C


I formatted an external drive, then set the boot up drive to be the external drive . When I rebooted, I restored the OS to the default, then upgraded and got most of what I needed to restore my setup from iCloud backups. I could see the internal drive as available while running the OS from the external drive.


After running this way for several months, I eventually went back to the internal drive as the boot drive. I did this because the external drive occasionally hung up during boot up. I always wondered if USB C was the best way to connect. Some things I did on the external - like upgrading the OS - forced the internal drive to be the boot drive after rebooting. I found that my original internal drive ran much better after reformatting and reloading the OS. Fortunately, I have an M1 laptop and didn't depend on the iMac as a primary computer.


I didn't provide step-by-step instructions because I went back to the original setup and wanted to give you an overview.



10 replies
Question marked as Top-ranking reply

Oct 28, 2023 6:58 AM in response to rony-z

I did this with a 2017 iMac to speed up everything with an external SSD connected via USB C


I formatted an external drive, then set the boot up drive to be the external drive . When I rebooted, I restored the OS to the default, then upgraded and got most of what I needed to restore my setup from iCloud backups. I could see the internal drive as available while running the OS from the external drive.


After running this way for several months, I eventually went back to the internal drive as the boot drive. I did this because the external drive occasionally hung up during boot up. I always wondered if USB C was the best way to connect. Some things I did on the external - like upgrading the OS - forced the internal drive to be the boot drive after rebooting. I found that my original internal drive ran much better after reformatting and reloading the OS. Fortunately, I have an M1 laptop and didn't depend on the iMac as a primary computer.


I didn't provide step-by-step instructions because I went back to the original setup and wanted to give you an overview.



Oct 28, 2023 7:17 AM in response to rony-z

If you have the time and the option to experiment, you might want to consider reformatting the internal drive and starting from scratch. I know this sounds like a lot of work but I actually enjoyed the process. Maybe reformatting would solve the internal drive issues.


Look at the refurbished iMacs on the Apple site to get a like-new computer and save money. I've done it a few times.

Tough question regarding using MacOS from an External Drive.

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