I have two MBPs connected together. One I'm booted into and the other is in target disk mode and has an erased drive. I try to run the Systemj installer and get a message that I can't install onto a Mac in target disk mode. Why? That seems pretty ridiculous. Is it some other Apple security issue?
Thanks.
They may have started preventing installing in TDM because of the issues of installing the wrong OS onto the target.
Since a Mac in Target Disk Mode is just an external hard drive to the host, it will install the OS for the Mac you are hosting from which may not be a valid install.
There may also be issues with creating the Secure Enclave because it cannot access the security information of the destination Mac.
What mac model is this?
In macs with T2 chip one has to explicitly allow external booting from external drives by changing the settings in Startup Security while starting from Recovery.
I expect something similar may be true in M1 macs.
Installing Mac OS is getting harder and harder for security reasons but, as already said, you should better have a bootable installer unan USB key and install from there. Not sure an internet connection WILL NOT be needed.
Whatever the reason you probably would be better off creating a bootable installer.
How to create a bootable installer for macOS - Apple Support
There shouldn't be any security information on it, though I understand the secure enclaves have indeed created a whole world of problems. Seems sometimes security is more of a nuisance than security.
Well, there certainly is on a Mac with a T2 chip and on M1 Macs. Apple has never appeared to make any decisions with concern for backward compatibility, so just ignoring all of the older Macs without such capability is not out of the question.
That does have a T2 chip. Hopefully that's not an issue. Since it successfully booted the installer it shouldn't be. But it's not something I've done on a Mac with a T2 chip. The only one I have is an M1 MacBook Air and I've had no reason to erase and install the OS.
Did you boot from it?
Make sure to read this section…
Use the bootable installer
Thanks. The tip explicit warns against trying to install onto a computer in target disk mode. The content though is dated. What's a DVD? ;) I still don't see why this would be prevent the installation. The computer in target disk mode is basically a blank external drive.
I started to try doing it from a bootable installer on a USB chip. The empty Mac sees the boot installer, but if I try to run it, it then wants to connect to the internet for some reason. What's that about? It's acting as if it has to go into recovery. Why? Recovery is so slow it will take the better part of the day. Sometimes Apple system software seems really stupid, or designed exclusively to be used on the fastest network servers in the world.
Good point. Thanks Barney.
There shouldn't be any security information on it, though I understand the secure enclaves have indeed created a whole world of problems. Seems sometimes security is more of a nuisance than security.
I booted with the option and it came up with the macOS installer. I selected it and it wanted a network. I then connected and seemed to be doing something, warned me that the system would shut down for a while. I'm now in shut down. Has it just shut down, or has it failed? This is dreadful software.
All else being equal it also works in Pittsburgh. Of course it is possible there may be an issue with the drive you are installing to. I would still wait it out. If nothing happens after another hour I would worry.
You're welcome. For the most part, it normally doesn't take all that long. However, there have been a few posts where it took hours before the install completed. As in 6 hours or more. I have no idea why.
Which MacBook Pro are you installing to?
Tom Wolsky wrote:
I guess you're using an OS whose name cannot be spoken.
Monterey can be mentioned. It just can't be discussed. 😎
Another issue may be where the installer came from. I was told that the macOS installers are binary, and can install to either Intel or M1, but I'm wondering if that is a problem.
It shouldn't be a problem but then again, I've never tried it.
Can the same disk install on an Intel or Apple Silicon Mac?
This reminded me of the time I booted one mac using a clone of the disk from a mac with a completely different architecture.
Not an installer, the actually system I was using.
The year was 2007, and the OS was... Leopard (10.5).
Ah! Nostalgia... 😎
You can't install on a Mac in target disk mode?
