macOS 15 Sequoia crashes, how to revert?

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Level 1

5 points

macOS 15 Sequoia crashes, how to revert?

I installed macOS 15.0 (stable) on my 16" MBP M1 Max, now it crashes immediately when the desktop should appear. After logging in, the progress bar runs pretty much all the way to the end, then it reboots. No unusual fan noise. Tried the following:

Unplugging external devices, booting in safe mode: Exactly the same, just takes longer.
Logging into another account with very little stuff installed: For a second I can see the menu bar, but no dock, before it crashes.
Tried to revert to local Time Machine snapshot: All of them, from before the update, are now shown as macOS 15.00 and only restore old user data, but not the OS.
Tried to revert to external Time Machine snapshot: You can't recover a backup of a previous OS version.
Tried to do online reinstall of previous OS: No longer available on M-series Macs.
Tried to create USB installer using an ancient MacBook Air: Installers only download on supported OS versions.

MacBook Pro 16″, macOS 14.6

Posted on Sep 18, 2024 8:57 AM

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Answer 1

Barney-15E

Level 10

123,828 points

Sep 18, 2024 9:16 AM in response to rbq

First create a bootable USB installer of the older OS. Since it is Apple Silicon you must make that installer on that Mac.

Use the USB Installer to startup the Mac.

If you have already erased or corrupted the Mac, you will be stuck trying to do this from Internet Recovery. That may require you reinstall Sequoia, then download the desired OS and make a USB Installer from that.

Erase the drive completely, Reinstall macOS, then Migrate from the Time Machine backup you made prior to upgrading the OS.

How to reinstall macOS - Apple Support

That article has links to how to erase and other ways to reinstall (bootable usb installer).

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Answer 2

Sep 19, 2024 12:19 PM in response to Barney-15E

Barney-15E wrote:

First create a bootable USB installer of the older OS. Since it is Apple Silicon you must make that installer on that Mac.

FYI, you can download & create a macOS 11.x+ USB installer using either an Intel or M-series Mac (of course that Mac must be compatible with the version of macOS installer you are creating). The resulting USB installer will boot just fine for both Intel & M-series installation. I confirmed this with Sonoma about a month ago when another contributors questioned if that would work.

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Answer 3

Barney-15E

Level 10

123,828 points

Sep 19, 2024 2:18 PM in response to HWTech

HWTech wrote:

Barney-15E wrote:

First create a bootable USB installer of the older OS. Since it is Apple Silicon you must make that installer on that Mac.

FYI, you can download & create a macOS 11.x+ USB installer using either an Intel or M-series Mac (of course that Mac must be compatible with the version of macOS installer you are creating). The resulting USB installer will boot just fine for both Intel & M-series installation. I confirmed this with Sonoma about a month ago when another contributors questioned if that would work.

When I tried that, early in Sonoma I think, the drive had to be reinstalled on my M1 Mini.

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Answer 4

Barney-15E

Level 10

123,828 points

Sep 18, 2024 10:50 AM in response to rbq

If you have enough space, you can just use another Volume.

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Answer 5

rbq Author

Level 1

5 points

Sep 18, 2024 10:13 AM in response to Barney-15E

Thanks, I created a new volume, downloaded and installed 15.0, then downloaded 14.7 from there.

Can I use another volume for the installer, or do I actually have to get an external storage medium?

My TM backup wasn't done using the latest 14.7 patch release. Will I still be able to migrate to transfer my backup data to the new installation?

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Answer 6

rbq Author

Level 1

5 points

Sep 19, 2024 12:32 AM in response to rbq

Update: I was able to reinstall 14.7 and restore from Time Machine. The whole experience was pretty terrible and I'm really disappointed that none of the straightforward ways that used to just work are available any more. I would have never thought that reverting to a previous backup would be this hard and require multiple macOS installations. Seems like the average user attempting an OS update would be better off using something like SuperDuper! or Carbon Copy Cloner instead of relying on Time Machine.

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Answer 7

Sep 20, 2024 12:29 PM in response to Barney-15E

Barney-15E wrote:

HWTech wrote:

Barney-15E wrote:

First create a bootable USB installer of the older OS. Since it is Apple Silicon you must make that installer on that Mac.

FYI, you can download & create a macOS 11.x+ USB installer using either an Intel or M-series Mac (of course that Mac must be compatible with the version of macOS installer you are creating). The resulting USB installer will boot just fine for both Intel & M-series installation. I confirmed this with Sonoma about a month ago when another contributors questioned if that would work.

When I tried that, early in Sonoma I think, the drive had to be reinstalled on my M1 Mini.

Yes, for booting the full installation of macOS that is true, but not for the USB installer. The USB installer will boot & work just fine on either platform.

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Answer 8

Steveor

Level 1

20 points

Sep 27, 2024 11:33 AM in response to rbq

I had the same terrible experience and had to do the same thing.

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