macOS 15.4 update failed on external disk

Last update from me, the release of 15.4.1 has resolved my issue for my dual internal volumes. Both are now up to date on 15.4.1, one upgrading from Sonoma 14.7.5 without any error messages. Both volumes also had FileVault enabled during the upgrade process. I hope that everyone else also has success with their external volumes - I am unable to test this currently.

Ditto, it didn’t work for me either. I’ve now gone the nuclear route of wiping the entire drive as I have time machine backups of everything, and would like to get my personal volume fixed. Prior to this I tried a first aid repair via disk utility in the recovery menu as recommended elsewhere but I still am unable to install macOS, either from recovery or USB.

I’ve just had a phone call with apple support who directed me to try wiping the device via the password recovery assistant, and I am currently a reinstallation from recovery which will hopefully be more successful!

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)

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.???

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 ....

Well glad to see there are a number of us with unusual setups.

Mine is Mac mini M2 Pro, bootable from external drive.

As with others, the internal drive updated to 15.4 no problem (as did my backup M2 Mini), but not the external drive. In 2 profiles, I have tried updating multiple times, in standard mode and safe mode. On the spare profile it goes through the procedure, but afterwards still on the old version, on my main profile I get the dialogue box saying my Mac has restarted after a problem.

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

I have 15.4 on my internal drive APFS. I made two external TB drives as boot drives (clone of my internal) and no issue using neither one. All my external drives are APFS with FileVault on.

And the external drive is connected to the non-DFU port?

I’ve had the same problem, except mine is with two different volumes on the internal SSD on my M1 Macbook Pro. My work side updated absolutely fine, but I was unable to update my personal side - it rebooted in a similar way to yours, but then just had an “We ran into a problem” style prompt with the option to report.

As there are a fair few vulnerabilities addressed with this update and I had not rebuilt my personal volume since I got the device, I thought I’d try installing from scratch but I’m hitting the same problem with just trying to install the OS on the separate volume, it doesn’t complete successfully and now I’m stuck with just my work volume.

Planning on doing some more troubleshooting at the weekend when I have some more time, but this isn’t ideal.

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.

Apple support were unable to resolve on the phone after trying another method of erasing the internal drive, so I need to take it in to the Apple Store for a service appointment, device is effectively a paperweight now.

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