Install Big Sur onto EXTERNAL SSD drive

I had the same issue with searches. Go to Spotlight (in System Preferences) and make the other drives not indexed

What external SSD would be recommended to run Big Sur on an external? Is USB enough or will I see a big difference if going with a Thunderbolt connection?
My machine is a 27" iMac 2017.


I used the 1 TB SSD that Glen mentioned in his article that I referenced. He had mentioned an OWC Envoy Pro EX that listed for just under $300.00. That is enough for me as my internal, slow hard drive is 1 TB. I’ve heard from some that they did a 2 TB SSD

I would NOT do this with USB drives. In fact the OWC SSD is only with a Thunderbolt 3 connection.

It is amazing how improved my iMac is

@jsabini I’ve got the same iMac as you and have been thinking of doing exactly what you did. Once you moved the accounts and data from your fusion drive, did you erase it or keep MacOS on it? If the latter, do you try to keep it in sync with the SSD? And are you doing nightly replication? I’m currently running Catalina on the Fusion drive and use SuperDuper! for nightly replication to an external USB 3 drive. Thanks!

Hey Andrew,

I did not erase my internal drive, I might down the road, or more likely use it as a data backup destination for the data partition, I’m not sure yet. I’m a little hesitant to nuke the internal drive, as I like having the peace of mind knowing I have another bootable drive I can count on.

I already had 2 external USB 3 drives as backups, one using Time Machine, and the other as a CCC destination. I will probably use the internal as a clone destination, and test it thoroughly before re-tasking the external clone to something else.

You certainly can do nightly backups/cloning, but for me a couple of times a week is sufficient.

Post when you make the transition and let us know how it goes! The Thunderbolt route really is the way to go, and I highly recommend any of the OWC products mentioned. I’ve purchased lots of upgrade hardware from them over the years, they know their stuff and stand behind it.

You should see a significant difference using Thunderbolt vs USB. I would not recommend going the USB route either.

Don’t waste money on all-in-one solutions when you can pick and choose better components yourself.

Probably one of the best 1TB prosumer SSDs you can get right now, $159 (2TB for $308)

And here’s a decent Thunderbolt 3 case for it with 50cm cable. $76

For less than $250 shipped, this combo will give you 2,500 MB/s throughout. Obviously, if you want to see that kind of performance over sustained periods, you’ll need an actively cooled enclosure. Or just point a fan at this one. :wink: