Level 1

99 points

Can't install macOS 15.4 on external volume

I am trying to install macOS Sequoia 15.4 on an external volume. The external volume is on an external drive and shares space with another volume. The drive is formatted APFS, GUI Partition Map and is connected to my Mac by USB 3 compliant USB "B" to "A" and USB "A" to "C" adapter. It is plugged into a Thunderbolt 4 port on the back of my Mac. My Mac is running 15.4.

I have tried various ideas but get the same end result:

the install is completed – it does a restart so I think it's complete;
the volume is locked;
the volume cannot be booted; and
so, the install process did not boot and enable a user account to be created.

I cannot find an installer log.

When the locked volume set as Startup Disk, there is an error "The version of macOS on the selected disk needs to be reinstalled.". When I try to run the installer again get another error: "This volume cannot be used since it has a secure token without any users. Please use Disk Utility to erase this volume.".

Things tried:

run installer from standard user account;
run installer from admin user account;
run installer from Recovery;
reduced startup security – have learned that is NOT necessary despite some Mac magazine articles;
toggled "Copy account settings from ....";
changed name of the Volume – took out space characters;
made sure the drive is NOT plugged into the DFU port.

Is installing on external volumes no longer possible ?

Mac Studio, macOS 15.4

Posted on Apr 8, 2025 9:35 PM

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LuizAlvarez

Level 1

14 points

Posted on Apr 12, 2025 4:01 AM

I have exactly the same issue. I own a M1 Mac mini and for almost three years I had a separate MacOS installation on an external thunderbolt nvme drive. Worked perfectly upgrading OS year after year. 15.4 comes, I am on 15.3.2 what could go wrong? . I go and update it, and suddenly get "The version of macOS on the selected disk needs to be reinstalled" . To further **** things down, for some reason my Time Machine backups don't work. I thought I'd have to upgrade OS on the integrated drive (big jump this time, from OS 12.x to 15.4) , and I managed to put it in 15.3.2, but I got the same message upgrading to 15.4 . I managed to install 15.4 on my internal storage using Apple Configurator - at the cost of erasing everything in there - though didnt have much in there. Once on 15.4 on the integrated storage I thought I could install 15.4 on my external drive (unrecoverable at this point) , and to my surprise, I still get the same error. Something is really messed up with 15.4 and Apple isn't acknowledging it.

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Garry Brooke Author

Level 1

99 points

Apr 9, 2025 5:58 PM in response to Owl-53

It's a need to. I'm a developer and I am trying to replicate an issue with my applet experienced by a user who is currently booting from an external drive. Otherwise, I have sufficient backup facilities. Your comment about Apple Silicon needing a functional internal drive is correct. The macOS installer will only enable installation on an external drive if there is a functioning admin account on the internal drive. Yes, next I will try to install on an entire drive. I'll also test installing on a fixed size partition.

Garry Brooke Author

Level 1

99 points

Apr 9, 2025 10:39 PM in response to Garry Brooke

UPDATE: Tried to install on a partition on an external drive – failed in same way as before. The partition was in a separate container and so did not share space with the other volume. Will now try to install on an external drive with one container of one volume.

Garry Brooke Author

Level 1

99 points

Apr 9, 2025 11:03 PM in response to Garry Brooke

UPDATE 2: Nope. Reformatted an entire SSD (GUID Partition Map) so that it had a single volume inside a single container. then tried to install macOS 15.4. As before, the install proceeds until "Closing applications and preparing to restart..." at which it hangs for some time then, it does a shutdown (I didn't see the usual "Startup in 30 seconds...." dialog). There is a startup bong then a very long delay (black screen at this point) then another bong and a quick startup from the internal SSD. Disk Utility shows there is an APFS System Volume and an APFS Data Volume.

So, I can't find any way of installing macOS 15.4 on an external drive. If anyone succeeds, please post here with details on how.

Garry Brooke Author

Level 1

99 points

Apr 10, 2025 3:55 AM in response to Ian R. Brown

Yes, that's my thought at present – I downloaded it from the App Store. A friend has another copy which has a different version, 20.3.04. I have been using version 20.4.02. I assume that there are changes which justify a different version number.

Garry Brooke Author

Level 1

99 points

Apr 11, 2025 9:28 PM in response to HWTech

Thanks. I did check that I was not using the DFU port. I chose an admin account during every install attempt. I had to enter the password for that account twice each time no matter how I invoked the installer. Don't think it's so bad I need to do a DFU revive or restore.

svmrw

Level 1

12 points

Apr 10, 2025 12:51 AM in response to Garry Brooke

You have the same thing that is discussed in the neighboring thread. The external volume has nothing to do with it

Unable to install macOS Sequoia update 15… - Apple Community

Apr 9, 2025 1:28 AM in response to Garry Brooke

Make sure you are formatting the Physical Disk and not the Volume.

In the View menu ensure that "Show all devices" is selected and in the Disk Utility window check that it says "Physical Disk".

Apr 9, 2025 12:45 AM in response to Garry Brooke

See other discussions related to Sequoia installation, recovery or update.

Garry Brooke Author

Level 1

99 points

Apr 9, 2025 6:05 PM in response to Ian R. Brown

Thanks for the link to the video. As mentioned, the entire drive is formatted GUID Partition Map.

Garry Brooke Author

Level 1

99 points

Apr 10, 2025 4:44 PM in response to Ian R. Brown

Ian, thanks. Yes, I did look at the video and I did format the entire drive in one experiment. Every time, I check that the entire drive is formatted GUI Partition Map. Cheers.

Garry Brooke Author

Level 1

99 points

Apr 12, 2025 6:01 PM in response to LuizAlvarez

Much the same happened to a friend recently trying to update a 15.3.2 install to 15.4 on an internal SSD. Lots and lots of errors and trouble.

Apr 19, 2025 1:47 PM in response to LuizAlvarez

15.4.1 is out. I could make a new MacOs install in my external drive, as it was before 15.4 F’d everything up.

Can't install macOS 15.4 on external volume

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