External OS Drive for Monterey - Will it work?

[Rockman53]

I am making a transition to Monterey but it warns me that the most valuable programs I use will not work without updating the programs.
Here's is my question. I would like to know, if I purchased an external thunderbolt Solid State Drive, would it be possible to install Monterey OS on that drive and then reboot switching to that drive as the Start-up Drive, so I can have both OS systems to switch between start up drives as needed?

 

[Howard Brazee]

I have an external startup Solid State Drive with Monterey on it. But using it is slow, slow, slow. I hope to upgrade to future MacOS versions there to verify that essential programs work on it. It is not a Thunderbolt drive and it is plugged in directly to my M1 iMac.

 

[TonyAguila]

I am making a transition to Monterey but it warns me that the most valuable programs I use will not work without updating the programs.
Here's is my question. I would like to know, if I purchased an external thunderbolt Solid State Drive, would it be possible to install Monterey OS on that drive and then reboot switching to that drive as the Start-up Drive, so I can have both OS systems to switch between start up drives as needed?

Sure you can install Monterey or any other macOS version on your external SSD, as long as your Mac supports it. Of course the external will be slower than your Apple internal SSD. I’m getting about 6,000 MB/s writes and about 5,400 reads from my Mac Studio’s internal SSD. I have four external Thunderbolt 3 SSDs which are SATA drives that are way slower than an M.2 NVMe SSD. My external SSD get about 350 MB/s writes and about 400 read.

When these were connected to my old 2018 Mac mini, I had Mojave, Catalina, Big Sur, and Monterey externals and they all worked well. Unfortunately, with the M1 Mac, I can only run macOS Monterey. I have an external Monterey system connected, primarily used for testing macOS updates prior to updating the main volume, or for troubleshooting purposes.

It’s surprising, though, because running from the external SSD does not feel that slow even if the speed tests show it to be almost 1/10th the speed of the internal. Still decent. And if your SSD is Thunderbolt 4 M.2 NVMe, it should be even faster. One thing to be aware of is that macOS upgrades can and probably will update the firmware of your Mac. For this reason, I still maintain my Mac mini to test beta versions of macOS. If the firmware update were to adversely affect the version of macOS that you normally run, it will not be possible to revert to the old firmware version.

Furthermore, you can also use the external SSD to run older versions of macOS, if you happen to have older apps that will not run in Monterey.

 

[Howard Brazee]

I wonder if my extreme slowness is due being USB rather than Thundebolt. I have a LaCie 2T Rugged drive plugged into my M1 iMac.

 

[TonyAguila]

I wonder if my extreme slowness is due being USB rather than Thundebolt. I have a LaCie 2T Rugged drive plugged into my M1 iMac.

Unless I’m mistaken, the LaCie Rugged drive is a spinner (hard disk), not solid state; so, yes, it will be glacial. If you want a speedy external SSD, you may want to try the Samsung X5. It’s an M.2 NVMe unit. Somewhat pricey, though, about $500 for 500 GB.

You may want to put one together. For about $400, you can have a 2-TB NVMe external SSD that runs faster than the X5. Assembly is easy. It will probably take 20 minutes to assemble. There are tons of videos on YouTube. Sadly the ones I’ve seen don’t show any precaution against static. These are sensitive electronics. If you decide to do it, make sure you take precautions. Make sure you have one of those grounding wrist bands.

Your M1 iMac will love it!

 

[Howard Brazee]

That could be, thanks.

 

[TonyAguila]

That could be, thanks.

This is a sample video. Don’t stop there—there are lots. I still cringe when I see them hadling the units without anti-static gear.

 

[Rockman53]

Sure you can install Monterey or any other macOS version on your external SSD, as long as your Mac supports it. Of course the external will be slower than your Apple internal SSD. I’m getting about 6,000 MB/s writes and about 5,400 reads from my Mac Studio’s internal SSD. I have four external Thunderbolt 3 SSDs which are SATA drives that are way slower than an M.2 NVMe SSD. My external SSD get about 350 MB/s writes and about 400 read.

When these were connected to my old 2018 Mac mini, I had Mojave, Catalina, Big Sur, and Monterey externals and they all worked well. Unfortunately, with the M1 Mac, I can only run macOS Monterey. I have an external Monterey system connected, primarily used for testing macOS updates prior to updating the main volume, or for troubleshooting purposes.

It’s surprising, though, because running from the external SSD does not feel that slow even if the speed tests show it to be almost 1/10th the speed of the internal. Still decent. And if your SSD is Thunderbolt 4 M.2 NVMe, it should be even faster. One thing to be aware of is that macOS upgrades can and probably will update the firmware of your Mac. For this reason, I still maintain my Mac mini to test beta versions of macOS. If the firmware update were to adversely affect the version of macOS that you normally run, it will not be possible to revert to the old firmware version.

Furthermore, you can also use the external SSD to run older versions of macOS, if you happen to have older apps that will not run in Monterey.

Hi Tony, Do you mean, even if I run Monterey from an external SSD, Monterey OS might change firmware "inside" my iMac? And if it does, I may not be able to run my previous internal OS? I think that is what you said?

 

[TonyAguila]

Hi Tony, Do you mean, even if I run Monterey from an external SSD, Monterey OS might change firmware "inside" my iMac? And if it does, I may not be able to run my previous internal OS? I think that is what you said?

That’s correct. It does not matter if the update is done on your internal drive or one that’s connected. That’s what happened to me after a beta update on my Mac mini and Monterey could not drive my second monitor. I was forced to downgrade to Big Sur until the bug was fixed after two or three more updates. Maybe it was coincidence, or not.

After I got my Mac Studio, I held onto the Mac mini to test macOS beta versions before installing it on the Studio. I posted this screen capture earlier, to show how to find the Mac firmware version in between updates. From About This Mac, click on System Report… and this window will open.

It’s probably not possible to revert change the firmware back, but it’s one way to narrow down possible sources of problems when it happens. This was taken July 4th, and today, July 7th, after installing Monterey 12.5 beta 5, my firmware is now 7459.141.1. Even if we don’t have any control over it, I think it’s good to be aware of what happens behind the scenes. If you are fortunate enough to have a second Mac as a test platform, you can at least have a chance at avoiding some of these problems.

My routine is to install the latest update on the old Mac (mini). If nothing blows up, install it on my external SSD. If nothing untoward happens, install it on the internal drive.

 

[Howard Brazee]

I have a 1T SSD which I probably should try to install Monterey on and see if that's faster, even if I can't install everything on it.

 

[TonyAguila]

I have a 1T SSD which I probably should try to install Monterey on and see if that's faster, even if I can't install everything on it.

Howard, that should work, even if the interface is USB-A. Of course Thunderbolt will be a lot faster. I suggest, to make sure, connecting it and erasing it as APFS. Then you should be able to run Blackmagic Disk Speed Test on it. It will surely be a lot faster than the external hard disk.

To install Monterey, you can use Recovery and select the SSD for installation. If you have the actual Install macOS Monterey.app file (the latest version is 12.4), it will make the installation much faster. You should also be able to download it from the App Store. Do a search for macOS Monterey. Click VIEW and then GET. It will start downloading to your Applications folder. When finished, it will launch automatically. Quit the installation (unless you want to install to your primary drive). Make a copy to another location, where you can then launch it and select the external SSD for installation.

Afterwards, Migration Assistant can get your data from your present startup drive. One terabyte should be plenty. If your present startup drive is more than 1-TB full, you can pick and choose which items to migrate to fit. My guess is that your internal drive is less than a terabyte full.

 

[Howard Brazee]

Howard, that should work, even if the interface is USB-A. Of course Thunderbolt will be a lot faster. I suggest, to make sure, connecting it and erasing it as APFS. Then you should be able to run Blackmagic Disk Speed Test on it. It will surely be a lot faster than the external hard disk.

To install Monterey, you can use Recovery and select the SSD for installation. If you have the actual Install macOS Monterey.app file (the latest version is 12.4), it will make the installation much faster. You should also be able to download it from the App Store. Do a search for macOS Monterey. Click VIEW and then GET. It will start downloading to your Applications folder. When finished, it will launch automatically. Quit the installation (unless you want to install to your primary drive). Make a copy to another location, where you can then launch it and select the external SSD for installation.

Afterwards, Migration Assistant can get your data from your present startup drive. One terabyte should be plenty. If your present startup drive is more than 1-TB full, you can pick and choose which items to migrate to fit. My guess is that your internal drive is less than a terabyte full.

It is greater than 1TB full. But I won't need stuff like my photos library or my music library. I have a program that needs to migrate with its license.

 

[TonyAguila]

It is greater than 1TB full. But I won't need stuff like my photos library or my music library. I have a program that needs to migrate with its license.

I had suspected as much. My Mac mini has a 1-TB SSD and my audiobook collection alone is about 650 GB. Then there are the photos, and music, and videos… I had to learn how to store them on external drives.

When I ordered my Mac Studio, I was determined to get the 4-TB drive, but it was way too expensive. I ended up getting the 2-TB SSD. I still have my audiobook and video collection on external storage.

 

[Howard Brazee]

That drive is much faster. But I couldn't do the migration. Unchecking most everything in my user should have freed up space. I created the drive with Available: 231.54 GB (767.87 GB on disk). That should be sufficient, but program I need to test doesn't think it's registered. Maybe I need a cloner program or to copy or restore my Library files.

 

[TonyAguila]

That drive is much faster. But I couldn't do the migration. Unchecking most everything in my user should have freed up space. I created the drive with Available: 231.54 GB (767.87 GB on disk). That should be sufficient, but program I need to test doesn't think it's registered. Maybe I need a cloner program or to copy or restore my Library files.

The only reliable way I can think of to migrate data is to use Migration Assistant. Did you have 767+ gigs on the disk before installing the system? I had assumed that you started out with a blank disk. Anyway, you can try migrating just your user folder first and leave the rest for later. Your settings and extensions are the most important things. Afterwards, you can run MA again to incrementally restore the rest. But it’s important that you have at least 25% available space.

Your other option is to back up/archive the 767+ gigabytes (if I understood you right) to another device and then completely erase it before trying the installation again.

 

[Howard Brazee]

I ended up deleting photos, music, & movies off my 2T LaCie Rugged drive, then using that drive to install MacOS to my 1T USB LaCie SSD. (I also turned off music on my iCloud settings)

I was surprised about how much faster that turned out to be, remembering that hard disks didn't use to seem that slow 2 Macs ago.