how do you set up an external hard drive as the startup disk for imac 21.5" retina 4k, 2017

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JimBill47 Author

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how do you set up an external hard drive as the startup disk for imac 21.5" retina 4k, 2017

how do you set up an external ssd as the startup disk

iMac 21.5″, macOS 10.13

Posted on Jan 18, 2021 1:22 PM

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Answer 1

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Old Toad

Level 10

208,397 points

Jan 18, 2021 3:52 PM in response to JimBill47

Yes. What system are you using now?

Also I'd use Carbon Copy Cloner

If you have trouble with CCC you can create a bootable flash drive according to this document and boot into it and select the SSD to install on: How to create a bootable installer for macOS - Apple Support

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Answer 2

JimBill47 Author

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Jan 18, 2021 2:50 PM in response to Old Toad

So...if I clone my current hard drive to the external drive, it would appear as a choice in the startup disk preference pane?

Then, I would select it to be the startup disk; click restart and we would have liftoff?

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Answer 3

JimBill47 Author

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12 points

Jan 19, 2021 7:56 AM in response to Old Toad

I'm on Catalina 10.15.7 (the last/latest version)

I have CCC

Now, I have to get the new external HD - looking at LaCie rugged Pro 2TB

anticipate using it just for the OS and Apps; all documents, photo files, etc

on other external hds.

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Answer 4

Old Toad

Level 10

208,397 points

Jan 19, 2021 9:31 AM in response to JimBill47

I strongly recommend one of the OWC SSDs. They are by far the more reliable available and have the best customer support I've run across. Look at these: OWC Envoy Pro EX . Check with customer support to see which type will give your iMac model the fastest speed.