Will MacOS on External USB3 Drive Running a Mac Mini Properly Operate an IMac?

[Midlandmorgan]

Exploring all options. Currently running a maxed out late 2012 Mac Mini off a USB3 drive, everything exactly as I want, but would really like to step up memory. IMac can accept more, mini can’t.

So I’m wondering if I can just take my current hi speed MacOS external drive, unplug it from the mini, and plug it into an iMac?

thanks

 

[chscag]

So I’m wondering if I can just take my current hi speed MacOS external drive, unplug it from the mini, and plug it into an iMac?

You could do that, but the question is... would that make a difference? Since you didn't tell us which iMac you're referring to, there is no way to know. Also, you state that the USB 3 drive is high speed. USB 3 is certainly not high speed.

I can boot my iMac (2017 27" model with 512GB SSD) with an external SSD (Samsung T5) and it will boot very quickly but still not as fast as from the internal SSD.

 

[Midlandmorgan]

Thanks...my current setup is with the original 5400 HDD, somewhat Jurassic by today’s standards. Which iMac, I don’t know.

if it matters, I use the machine for ProTools, Cubase 10.5, Studio One 3.5...

When booting from current internal it takes well over a minute...booting with external takes about 20 seconds

 

[chscag]

Okay. Yeah, unfortunately the 5400 RPM drives are slow so I can well understand booting from an external USB 3.0 drive. Have you thought about changing that drive for a SSD or at least a 7200 RPM drive? Instructions at www.ifixit.com are not all that difficult to follow.

 

[Midlandmorgan]

Yeah man...thanks!

 

[Fishrrman]

OP:

You didn't tell us about the iMac...
- What year?
- What kind of drive inside?

You could boot a new (or relatively "newer") iMac from a USB3 external drive, even if the OS on it was previously running a Mini, so long as you were running a version of the OS on it that is capable of booting the iMac in question.

HOWEVER --
That's not the way you want to do it.

Get an iMac with a factory-installed SSD, and it will be MUCH faster than any USB3 external SSD, by a factor of 4x or 5x.

For audio apps, a 27" iMac from 2019 (or even an Apple-refurbished 2017) with an internal SSD will "hit the spot"...

 

[Midlandmorgan]

Actually I kinda did..

2012 , 16G ram, 5400 stock drive.

It’s been running right nicely with High Sierra coming off a SSD, audio being run back and forth on thunderbolt drive, interface via FireWire 800. ProTools 2018 with some 20-25 track projects at 24/48K, doing everything it’s supposed to with nary a hiccup. When running with the factory drive and a FireWire audio drive, it would bog down after 12 tracks or so.

All seems well now. Waiting for delivery of an OWC thunderbolt 2 dock, and be rid of spinning drives altogether.

 

[wizbang68]

Exploring all options. Currently running a maxed out late 2012 Mac Mini off a USB3 drive, everything exactly as I want, but would really like to step up memory. IMac can accept more, mini can’t.

So I’m wondering if I can just take my current hi speed MacOS external drive, unplug it from the mini, and plug it into an iMac?

thanks

You may get lucky and have it work, however it's more likely that you will have problems because the EFI lives on the HDD with OS being booted. Since the Mac Mini has different hardware it could cause the OS to be all kinds of messed up. I know because I tried doing something similar with a MacBook and my iMac. It ended up corrupting the SSD within a week of using it on the iMac with the OS configured for the MacBook. It was a painful lesson for me to learn.

The iMac won't run an OS that was released prior to the introduction of your iMac model. When you look at "about this Mac it will have a model identifier. For example the 2019 27" iMac is 19.1. Use the model identifier on the Apple website to find out the OS the iMac was released with. You can only run an OS that was installed initially on that iMac or a more recent version. A earlier version won't be functional.