macOS 15.4 update failed on external disk

I have the same exact problem on my M1 MacBook Pro.

But no external disk for me, just internal one.

Was updating from macOS 14 and it kept giving me the “your computer stopped unexpectedly” error after reboot…

eventually I manually upgraded to 15.3 but from there 15.4 still won’t install

I have the same problem.

I always installed the OS and on an external disk for testing.

With version 15.4 so far it is not possible. i deleted from scratch both internal and external.

I installed on the internal with UDF procedure. On the external, but also on the internal partition it installs but does not boot from there and gives an error.

I believe it is Apple's fault and they need to fix it immediately before we lose everything.

It's no coincidence that they still haven't released 15.4 in APPSTORE.

This is the same situation I’m in now, with a non-working device and the same select startup drive error you mention after erase and reinstallation. I have an appointment on Saturday with the service center and will provide an update then. Looking at some other threads on discussions, some have advised trying a DFU revive/restore, but you need another mac running 15.X to do that which is not something I have access to currently.

Update after my visit to the Apple Store for a service, they were successfully able to perform a DFU restore via Apple Configurator. Took about 15-20 minutes to complete, and the OS is now installed correctly with 15.4.

When I get home I'll try re-creating my separate volume for work and will begin the setup process for that, and report if it is successful. The technician seemed to think it may be something related to FileVault causing the issue, which may have affected the preboot partition although I'm surprised fully wiping the disk didn't fix that. So if you have access to another Mac running 14/15 with USB-C, you may have success doing a DFU restore. Note this will require the device itself to be wiped. As my device as already wiped the tech did not try a revive which also may have been successful.

That's right with DFU Mode I did it too.

I installed correctly on the internal drive in this way version 15.4. But then on the external drive it could not be installed even though it does all the splitting and copies the files.

After rebooting , when it should have started from the external drive, it starts the system on the internal drive with the error forced reboot due to error ....

Sad to say I've hit the same thing now. While my personal volume is now working fine post DFU, I've just tried to create my work volume again on the internal drive and install 15.4 to that, but I'm hitting the exact same problems again. The tech said it might be FileVault related, so I've also tried disabling that and installing again but it didn't work.

The other main thing that worries me at the moment besides being unable to use this device for my normal work setup, is that if for whatever reason I need to reset my Mac and start again from scratch, I'll need a DFU restore in order to do that since any fresh installation of Sequoia seems to fail, regardless if it's from the App Store, a USB drive or the recovery mode. It's not exactly a quick trip to my local Apple Store either.

Did you do anything different to get the successful install, or just perseverance?

Latest update from my end is that I have now installed 14.7.5 as my work volume as recommended by a senior apple technician and am stuck using that at until the issue is resolved apple’s end.

To summarise, I have a personal volume on 15.4 which was restored via DFU since device was in a non-working state after erasing the drive to try and fix, and a work volume on 14.7.5, both on internal SSD. I tried the upgrade from 14.7.5 to 15.4 but this failed in the same way as the others had previously. Apple support have raised this with their engineering team and I’m currently waiting to hear back. The technician I was speaking to seemed to think it would be something that would need to be resolved with a 15.4.1 type patch once they have identified the root cause.

My device is a base model 14 inch M1 pro (2021)

Mac mini M4, macOS 15.3.2 on external SSD here (FileVault enabled),

tried

sudo softwareupdate --fetch-full-installer --full-installer-version 15.4.1 --launch-installer -R

No luck, update can perform until the next login screen, still crashed and rolled back after password input

Hello Everyone,

I had the same problem. The installer doesn't work. I am running an Samsung 990 pro in a Thunderbolt ZikeDrive USB4 40Gbps NVMe M.2 SSD-Enclosure enclosure on a MacBook Pro 14" 2023. I could not install the update no matter what I tried. I ended up making a clone of my data via Carbon Copy Cloner and then did a clean install with a bootable disk from the latest version of MacOs Sequoia 15.4.1 available in the AppStore. That worked an then I transferred my data back wit migration assistant. It was work but now everything works like a charm. Hope this helps.

Update..... I finally was able to install 15.4.1 on to an external drive... !! :-) Here is how I did the install onto an external drive... I put the Sequoia 15.4.1 installer onto my emergency disk which had Sequoia 15.3.2 -- . and ran the installer from there..it worked fine.. Migrated all my info from Internal disk which is still running Sonoma 14.7.5 .. I have not yet updated the internal drive ....not sure whether to clone the external drive? or try and run the update again on internal drive?

NOTE: BUT _ I still cannot update the 15.3.2 on my emergency disk to 15.4.1.???

Here is related topic Ithink: M1 macbook pro fails to upgrade to Sequoi… - Apple Community

Afraid not, both of my volumes are normal APFS. I've also since tried reinstalling macOS again using the recovery mode and a USB recovery drive, while creating a new volume for personal use without success. I've attached the error log output that I am receiving when it reboots automatically into my work volume after the failed install.

It looks like something is causing a kernel panic during the initial setup after reboot. I've reported it to apple using the built in prompt.

I have a similar issue here.

I have been trying to install MacOs on external drive without any success, here what I have tried:

• SSD EMTEC 480GB
• sigle portion as APFS with GUID boot partition
• downloaded installer macOS Sequoia version 20.2.05
• launching installer and followed all the steps selecting the external SSD
• after a while it shows up the same message:

An error occurred preparing the update.

Failed to personalise the software update. Please try again.

• tried to connect the external SSD to the non-DFU port (which is the leftest on the MacBook Air M1 2020.
• having the same error message.

Any help please?

Many Thanks