Install High Sierra on external drive...

ultradk

macrumors member
Original poster
Oct 1, 2009
32
5
Denmark
but I am running Sierra. Is this possible? I am not willing to install High Sierra instead of Sierra as of yet.
 

Racineur

macrumors 6502
Jun 11, 2013
299
61
Montréal, Québec
Hello, High Sierra on an external SSD is my exact setup. it's on a 250 g Samsung. Fast and furious, Also I have Sierra and Mojave and El Capitan on another external SSD. Mountain Lion (yes) is still installed on the internal Fusion Drive of my late 2012 27 iMac. I assure you there's no problem at all. As far as it goes for me, the fastest boot and performances go to Mountain Lion, El Capitan, Sierra, High Sierra and Mojave in that order. Strange but not so much.
 

ultradk

macrumors member
Original poster
Oct 1, 2009
32
5
Denmark
Sure you can do that to try it out. It'll work fine.
I was trying but got an error.. and I don't know if it's possible.

I want to test High Sierra on external drive before I go all in on my late 2012 iMac with fusion drive..
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Hello, High Sierra on an external SSD is my exact setup. it's on a 250 g Samsung. Fast and furious, Also I have Sierra and Mojave and El Capitan on another external SSD. Mountain Lion (yes) is still installed on the internal Fusion Drive of my late 2012 27 iMac. I assure you there's no problem at all. As far as it goes for me, the fastest boot and performances go to Mountain Lion, El Capitan, Sierra, High Sierra and Mojave in that order. Strange but not so much.
So no error when install High Sierra on external drive with Sierra on the main machine?
 

chabig

macrumors 603
Sep 6, 2002
6,070
3,307
It doesn’t matter what’s on the main drive. You can always install and run macOS on an external drive. What is the error you see?

Edit: You didn‘t say what machine. Is this a T2 Mac?
 

ultradk

macrumors member
Original poster
Oct 1, 2009
32
5
Denmark
It doesn’t matter what’s on the main drive. You can always install and run macOS on an external drive. What is the error you see?

Edit: You didn‘t say what machine. Is this a T2 Mac?
I just got everything working. I wasn't getting the full installer of High Sierra, but got it another way around (I think macworld had the article) - I was able to install it on external drive and run it yesterday.

I am a little afraid of installing on my machine (fusion drive) since I want it to be snappy as Sierra is.. when trying on external drive it's not that fast. I know its a mechanical drive.. and frankly how is everyone getting around old programs that not can be running on High Sierra. I really like mpegstreamclip and I can't find any better free program for edit without convert. But there are others..
 

Racineur

macrumors 6502
Jun 11, 2013
299
61
Montréal, Québec
Friend, I highly recommend that you buy an external SSD and install High Sierra on it. Believe me, it's very very fast. Actually, faster that the OS that sits on your internal HD would it be a Fusion Drive. I agree with you about old programs. That's why I kept Mountain Lion on the Fusion drive. It runs "old" apps like Nikon NX 2 and Aperture very fine,