Unable to install macOS Sequoia update 15.4 on my MacBook Pro

I've already tried downloading a full version of 15.4. I get a pop up window saying there was a problem with the update. it only tells me to ignore or report. WTH is going on?

I've experienced the same error yesterday and I've tried the command this morning. Here's the result

softwareupdate --fetch-full-installer --full-installer-version 15.4

Scanning for 15.4 installer
Install failed with error: An error occurred while running scripts from the package “InstallAssistant.pkg”.
Error Domain=PKInstallErrorDomain Code=112 "An error occurred while running scripts from the package “InstallAssistant.pkg”." UserInfo={SUErrorUpdateTitle=macOS Sequoia, NSURL=file:///Library/Updates/082-16524/InstallAssistant.pkg, PKInstallPackageIdentifier=com.apple.pkg.InstallAssistant.macOSSequoia, NSLocalizedDescription=An error occurred while running scripts from the package “InstallAssistant.pkg”., SUErrorRelatedCode=SUErrorCodeInstallFailure, NSFilePath=./postinstall.sh, SUErrorUpdateProductKey=082-16524}

Here is how I fixed. Maybe there is shorter path to do this.

1. run command

`sudo softwareupdate --fetch-full-installer -a --launch-installer -R`

It will download full installer into /Applications

2. Start installer Install macOS Sequoia.app from Applications

3. selected disk and proceed to the process where progress bar appeared and estimation time showed up, wait a bit and then cancel.

I think at this point it did some cleanup.

4. Went back to the System Settings and click on Update.

Now I see message to accept terms and conditions, click agree and it starts downloading update.

From this point at goes as normal.

Had same problem: couldn't update from 15.3.2 to 15.4.

No error codes, just a message that update couldn't be installed.

Solution: shut down computer, reboot in safe mode (hold power button and when choosing volume: hold shift).

Then run update.

This morning, I contacted Apple Support to continue troubleshooting after backing up my important documents. I explained the steps I had taken and shared insights I found online from the apple forum. They informed me that I would need access to another Sequoia Mac in order to attempt further recovery methods. Unfortunately, my only remaining option would be to wipe and reinstall, although they cautioned that this might not resolve the issue, as the M-series chips don’t allow downgrades.

As an alternative, they recommended scheduling a Genius Bar appointment, where they would have the necessary tools to explore additional recovery options before resorting to a clean install. I’m heading in this afternoon to see if any progress can be made before taking that final step.

We've been facing this at my workplace. I spent some time testing things and the one thing that actually ended up working is running the following script:

sudo softwareupdate --fetch-full-installer --full-installer-version 15.4 --launch-installer -R

Pretty much pulls the full installer for 15.4 and will download it to your Mac. It should auto launch the installer after (Don't worry it will not wipe the device). If it doesn't auto launch the installer should be in the applications folder in finder.

Same here. The organization I work for has ~150 Macbook Airs. Most have upgraded without issue, but there have been ~20 that either reboot back to 15.3.2, or get stuck in recovery mode. For the ones that reboot to 15.3.2, I've had some success starting MacOS in Safe Mode and installing there. But the ones booting to recovery, reinstalling from recovery doesn't fix it. The most reliable way to get them to 15.4 though is to put them in DFU mode and restore them from another Mac.

I faced this issue a few days ago. I'm on a 2021 M1 Pro 14" MacBook Pro. Standard delta 15.4 update didn't work. Was unable to use 'terminal' command to download full installer. Downloaded the full 15.4 installer from the App Store and created bootable USB. Bootable USB didn't work. The only thing that did work was a 'DFU restore' by plugging into a secondary Mac and using Apple Configurator app from the App Store. This procedure finally gave me the clean install I wanted and updated the base recovery image on the Mac to 15.4.

I usually do a clean install on my Mac once a year usually on the pre WWDC MacOS release. The 2021 M1 Pro machines that shipped with macOS Monterey have been glitchy when doing 'clean installs' (erase & install). Hopefully the DFU restore has resolved this.

Have you tried the DFU “Restore”? That’s what fixed things for me. It requires another Mac and “Apple Configurator 2” app (which is free in the Apple App Store). It resets your firmware and reinstalls the system. Many have speculated that this problem traces back to corrupted firmware.

I tried everything else with my M1 Max MacBook Pro and this is the only thing that worked.

There should be several posts in this thread about how to do it. The video below was very helpful to me as it steps you through the whole process. Video link here:

https://www.youtube.com/watch?v=q-FsB2onSx0

I hope this helps.

Many users with M1-based Macs are experiencing serious issues when trying to install or upgrade to macOS Sequoia 15.4. These include kernel panics, repeated reboots, “unable to downgrade” errors, and the message: “The version of macOS on the selected disk needs to be reinstalled.” This happens both with standard upgrades and clean installs. It appears to be a software bug introduced in macOS Sequoia 15.4, likely affecting Apple Silicon (M1/M2) systems due to low-level driver changes (e.g., AppleT8020DART).

Here is a working solution:

• Download the earlier version of macOS Sequoia 15.2 on another Mac.
• Open Terminal and run:

softwareupdate --fetch-full-installer --full-installer-version 15.2

• Create a bootable USB installer.
• Plug in a USB drive (at least 16 GB), open Disk Utility, and erase it using:
  • Format: Mac OS Extended (Journaled)
  • Scheme: GUID Partition Map
  • Name: MyInstaller
• Then run in Terminal:

sudo /Applications/Install\ macOS\ Sequoia.app/Contents/Resources/createinstallmedia --volume /Volumes/MyInstaller

• Boot your M1/M2 Mac from the USB installer.
  • Shut down the Mac.
  • Press and hold the Power button until “Loading startup options” appears.
  • Select the USB installer and click Continue.
• Erase the internal disk. This step is critical:
  • In the macOS Utilities screen, open Disk Utility.
  • Click “View” and choose “Show All Devices.”
  • Select the top-level internal disk (e.g., “APPLE SSD”).
  • Click Erase, and follow the prompts.
  • On newer Macs, you’ll see a simplified prompt saying that all data on Macintosh HD will be erased and the Mac will restart.
  • Confirm and proceed.
  • Do not attempt to erase “macOS Base System” or any “macOS disk image” — these are part of the USB installer and should remain.

Important: This will permanently erase all user data on the Mac, including files, applications, and settings.

• Reinstall macOS Sequoia: After the Mac reboots, it will return to the macOS installer. Proceed with installing macOS Sequoia onto the newly erased disk.
• Once installed, your Mac should boot normally into Sequoia 15.2 without the issues seen in 15.4. Avoid upgrading to 15.4 until Apple releases a fix.
• If you already attempted to install 15.4 and are now stuck, you must erase the disk as described above. Simply trying to install an older version like 15.2 over a failed 15.4 install will usually result in errors such as “unable to downgrade."

Additional note:

Recovery Mode requires an internet connection to fully function. When entering a Wi-Fi password, your keyboard may default to a QWERTY layout, even if your usual layout is different. Changing the layout from the top-right language selector may not work, so you should type your Wi-Fi password as if using a QWERTY keyboard.

Just updated to 15.4.1 and it worked!

If 15.4 didn’t work for you, give this one a try.

That's great to hear! 😄

There will be many folk who have been posting and reading in this thread who will be very pleased!

Try booting into Safe Mode according to How to use safe mode on your Mac and and installing from there. I've had some problems installing updates in the past and booting into safe mode did the trick for me. I must have had some 3rd party software that was interfering with the installation.

NOTE 1: Safe Mode boot can take up to 3 - 5 minutes as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

You might want to try clearing out any leftover update files and resetting the software update settings, those steps can sometimes fix weird issues where macOS updates fail without a clear error. There's a guide that walks through those and a few other things worth checking: Fix macOS Sequoia Not Installing on Your Mac

Wow! It did help to solve my issue. Mac started to download 6,17 GB update, during installation it restarted 5-7 times and now I'm on macOs 15.4!

The only thing I needed to change is the terminal command to download eaxctly 15.4 version:

softwareupdate --fetch-full-installer --full-installer-version 15.4

But I needed to wait till the download completes, go to Applications folder and launch the installer manually.

I think I could have just adjusted your command to

sudo softwareupdate --fetch-full-installer-version 15.4 -a --launch-installer -R

My 2018 Intel Mini on 15.3.1 also refused to install. It would do the download, tell me the installation would take 30 minutes, then hang at that point for 10-15 minutes without updating the estimate, then report that there was some unspecified problem and I should try again. It failed the same way three times.

(I had exactly this misbehavior from an earlier update issued about a year ago, and couldn't get around it. I finally gave up, and it installed itself without my help a month or so later.)

This time, I downloaded the full installer into /Applications from the Apple Store, then rebooted into Safe Mode and ran it manually. It gave me no further problems.

Note that I ran this same update on my M3 MBP two days ago without any of this grief occurring.