CompileSwift Podcast – Install macOS Monterey on an external drive


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Season 3 Episode 4

I will talk about my experiences installing the macOS Monterey beta on an external drive, or at least my attempt to do so; you will have to hang on until the end to find out if it is successful.

During the WWDC21 conference, I held off installing the betas because I wanted to let the dust settle and see how it went with other people.

I went ahead and installed the first beta of iPadOS 15 on my iPad Pro 12″,
It's not the M1 version; it's the version before that. I have to say so far, other than many problems with safari. Everything else has been pretty good and pretty reliable. So that's all I'm going to cover there on the iPad.

I may dive into iPadOS 15 in further detail in the future, I've just installed the beta two, but I haven't had a chance to look at it yet.

What was more interesting to me was the fun times I had with trying to install macOS Monterey. Now, before I get into how I did it and how it worked, I want to go into a couple of details, why this is more complicated than it is when you're installing on an Intel chip.

First of all, I do not install the betas on my production machines. It's just silly to do so, and you're just pushing your luck if you do that. I do not recommend it at all.

Every year, I install on an external SSD drive, and then I find that the performance almost as good as an internal drive.

At least, the performance loss is barely noticeable to me, to be honest, in a very non-scientific way. So I decided this year to do the same thing.

But the difference this year is I've got an M1 MacMini. So what makes it more complicated?

With the Intel chip, you used to reboot your machine in recovery mode and install.

Not how it works on the apple chip. So I guess they've got their reasons for this, but you can't just boot from an external drive, install and reboot.

I say this in theory because the details proved otherwise, but in theory, you cannot just format an external drive, install it, and boot because of an extra option.

I tried many different ways to install it on an external APFS file system and make it bootable. I want to stress that all the failures worked because it installed it on the drive, but it would not let me boot.

The reason is due to the extra layer of security. M1 chips require you to lower the protection of the drive to boot from it. The way you do that on a MacMini, I will assume it's the same on the laptops, is to hold down the power button until you see a message come up on the screen, keep your finger on the button. And it'll say, keep pushing the button to get into the configuration options takes approximately 10 seconds. Then, once you see loading up the options, you can take your finger off the power button.

It goes into the standard recovery mode that you will have seen before if you've ever done that on a Mac where you have the options, among other things, to reinstall the OS. Access the drives and the drive utility. Now there's also an extra option to set the security for the drive.

And essentially, there are two, two options. You have. One is full security, very cleverly labeled by apple. Then there's another one, which is lower security. And what that does for us is allow us to boot from external drives.

So that's the option you need. That's the key right there, to boot from other drives. Now that didn't work for me because I tried many different ways, but I went into the recovery software at the end of the day and formatted my external. Installed, macOS Monterrey on it.

And when rebooted, it got into a loop. One of two things happened. It either makes a loop. I keep going back into the recovery mode, or it would boot into my standard big Sur on the internal drive.

I tried to lower the security on the external drive. And when I did that, you have to have an administrator account on that drive to log into it and set the options. Well, that's the first problem. I've done a fresh install of the OS, it doesn't have any accounts on there yet, so I cannot log into it.

And when I tried to lower the security, of course, it says, Hey, there's no administrator account on this drive. So that is the first loop of going nowhere. So as I went through this for a couple of days, trying many different options, it just didn't work.

Now, here is the key to how I got it to work. And it's so silly, but hey, it's beta software. As developers, again, this is why you don't install this stuff on your regular machine.

If you have any problems, here's the solution that worked for me.

The first thing I had to do was the very thing I didn't want to do, upgrade my internal drive to macOS Monterey beta. It was the only way to get this to work. After the upgrade was complete and the machine rebooted. I rebooted the machine again and went into recovery mode.

I formatted my external hard drive as APFS with the GUID partition and then installed macOS Monterey beta. This time when the machine rebooted. I got the option to select the language and do a macOS setup, which was weird because firstly, I want to point out here, I had not been able to lower the security of this drive or the machine because I hadn't had the option to do so.

Theoretically, this shouldn't even be possible because of the security options, but I went ahead and configured it, and everything was fine.

Now, at the end of the setup, I had an administrator account on that external drive. So I rebooted the machine again, went into recovery mode, selected the external drive, and I was able to lower the security. However, it seemed pointless now because I'd already got into the machine.

I lowered the security settings, rebooted the machine again. Now I had my working macOS Monterey beta one on an external drive.

Now comes the next part of the problem because I want Big Sur running on my internal drive. That was the whole point of this, not to touch it.

Well, you can't just downgrade to Big Sur on the internal drive. You can try and do it because I did. And it'll tell you, Nope, can't do that. So I had to reboot the machine into recovery mode and reinstall Big Sur. Luckily I have the installer on a thumb drive.

So I recommend you have two thumb drives, one with Monterey one with Big Sur. I reinstalled big Sur on my internal drive.

An important note here is that I did not format the drive. So all of my data was protected on the data partition.

Fingers crossed, I rebooted the machine on the internal drive, and sure enough, Big Sur had some problems. I had to redo many permissions for software.

It took at least a day to get through all the usual things, like finding those permissions that pop up. Some software licenses also needed reinstalling, but Hey, it worked.

At the end of this, I have an internal drive with Big Sur that boots and an external one with Monterey.

There is no short version of this story because all of these details are important. If you have any problems trying to install it on an external drive, I recommend trying the path that I describe above.

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