Failed Beta Update 15.4 - M4 Mac Mini - Can't Reinstall

[neobow2]

Last night I updated my M4 Mac Mini to the latest developer beta. This morning when I went to use the Mac, I noticed that the update had failed and was boot-looping/going into recovery mode.

In Recovery I get told that "The version of macOS on the selected disk needs to be reinstalled". I then follow the instructions and get to "Reinstall macOS Sequoia" which then proceeds to not let me do because "The volume cannot be downgraded"

What are my options here? I really can't stomach loosing any of the data as I use this Mac almost exclusively for my work.

UPDATE - Here is how I reinstalled without loosing data:

1. In Disk Utility, create a new SPFS Partition (I named it "New Partition").
2. Go back to Reinstall Sequoia and select the "New Partition" volume.
3. Once that reinstalls, Set it up with your Apple ID (assuming you did before)
4. Go to Software Updates and update to latest version (I updated to 15.4 again, this time successfully).
5. Open migration assistant
6. Select from a Mac or startup disk then press continue
7. Select the old startup disk (likely "Macintosh HD")
8. If you created the same username for the New Partition version, select "Replace user" and un-click copy files
9. Enjoy!

* If you (like me) encounter an error in the migration assistant saying "not enough storage to migrate user" then you will need to use an external drive:

1. Install CCC (Carbon Copy Cloner) use the free trial or support the dev because it's super useful
2. In CCC, copy the "Macintosh HD" drive to your external drive (like USB Drive).
3. AFTER confirming that the data has been backed up correctly, erase the "Data" volume from "Macintosh HD".
4. Return to Migration Assistant and select the external drive volume as the source.
5. Refer to Step 8. from above

 

[Bigwaff]

I really can't stomach loosing any of the data as I use this Mac almost exclusively for my work.

Do you have a back up of the system at all?

 

[r8ders2k]

Exactly, did you back up before doing the 15.4 beta update? IF it's not a major, can't boot, it's borked... You're most likely going to have to wipe and reinstall, and then restore from your backup. And if that doesn't work, you'll probably have to make a Genius Bar appointment.

 

[BigBlur]

This beta is known to have some severe bugs. People are having trouble rolling back too. Need to put the Mac in DFU mode and use another Mac to restore the firmware (or go to the Genius Bar). I hope you have a backup!

https://www.reddit.com/r/MacOSBeta/comments/1iv2ukx/macos_154_beta_1_crashes

 

[Azkylinegtr]

I have been using an external boot drive with all betas thus far. I get a black screen with no response when trying to update to the latest beta from 15.3.1 after a very long time I get that same error. If I try to install in recovery mode it tells me the external disk cannot be downgraded. Internal works fine. After doing a reboot and not doing the recovery my external boots back up to 15.3.1 like it did before. I went through this cycle trying to upgrade 3-4 times and it always did the same thing.

 

[IowaLynn]

I am on beta channel and the update prior to today, Tuesday, was the longest, scariest update I've ever seen. Took 30 minutes or more, didn't time it. 2020 Intel Mini 16/512.

When it was done storage showed ~15GB free! after today's update now shows 130GB free. Much safer.

Multiple TimeMachine, an older CCC clone or two (haven't done paid upgrade yet).

 

[neobow2]

Do you have a back up of the system at all?

Looks like I do not. I'm trying to do the Share Disk option right now to save as much data as possible. There's got to be a way to be able to reinstall without loosing all the data drive information

 

[IowaLynn]

> I really can't stomach loosing any of the data as I use this Mac almost exclusively for my work. <

You’ve already gathered but maybe worth repeating - Never mix business and pleasure, unless you develop software or need to certify a software package’s compatibility with an upcoming version of the system, and then take necessary precautions.

Redundancy, multiple backup methods. Time machine can manage multiple backups so you have daily backup disk, weekly, and monthly. As example. And clone your system, twice at least.

Stock up on drives.
A 2nd Mac would be good investment.
Otherwise… leave dev and public beta behind.

There can be updates to Mac firmware, drivers, chip controllers, as well as the general OS. Meaning low level changes.

Professional recovery software tools. 🛠️

 

[Bigwaff]

Looks like I do not. I'm trying to do the Share Disk option right now to save as much data as possible. There's got to be a way to be able to reinstall without loosing all the data drive information

Shot in the dark ... in Recovery, change the Security Policy to Reduced Security. Reduced Security should allow any version of signed system software to run. Perhaps it will allow you to install an earlier version of Sequoia.

 

[Mr. Mac Mini]

Looks like I do not. I'm trying to do the Share Disk option right now to save as much data as possible. There's got to be a way to be able to reinstall without loosing all the data drive information

Once I did something in recovery mode that I shouldn´t have done – don´t remember what – and after that a question mark with the text "contact Apple support", or something along those lines, prompted to the screen.

I shut down the computer(Intel iMac) and then started it again in recovery mode. Soon to the screen appeared the globe icon – and after a while Mac found an OS from the net and installed the originally installed version to the machine.

 

[neobow2]

> I really can't stomach loosing any of the data as I use this Mac almost exclusively for my work. <

You’ve already gathered but maybe worth repeating - Never mix business and pleasure, unless you develop software or need to certify a software package’s compatibility with an upcoming version of the system, and then take necessary precautions.

Redundancy, multiple backup methods. Time machine can manage multiple backups so you have daily backup disk, weekly, and monthly. As example. And clone your system, twice at least.

Stock up on drives.
A 2nd Mac would be good investment.
Otherwise… leave dev and public beta behind.

There can be updates to Mac firmware, drivers, chip controllers, as well as the general OS. Meaning low level changes.

Professional recovery software tools. 🛠️

Yeah, I got complacent since I hadn't had any failed firmware update issue like this in my 10 years of using Betas macOS/iOS. (That's a lie, convinced my dad to use beta iOS 12 and he got boot looped, but it's been a while)

Thankfully I was able to not lose any data by creating a new partition (guide in update). That being said, I am now interested in getting some sort of external raid set up for Time Machine backups.

 

[Ens]

I’ve found myself in the same pickle; getting complacent due to never having issues with betas in multiple years of using them, to now having a botched update to the latest MacOS Tahoe public beta on my M3 iMac. Without having backed up.
Luckily I do have all my documents and files on iCloud Drive, and my Photos on an external SSD, but I’d still like to keep all my stuff as is, if possible.
I’m following your guide to reinstalling without wiping the disk, but I don’t understand how to download CCC on the affected Mac 🤔 or should that be on a different Mac?
If so, how does that help me on the affected Mac?

 

[neobow2]

I’ve found myself in the same pickle; getting complacent due to never having issues with betas in multiple years of using them, to now having a botched update to the latest MacOS Tahoe public beta on my M3 iMac. Without having backed up.
Luckily I do have all my documents and files on iCloud Drive, and my Photos on an external SSD, but I’d still like to keep all my stuff as is, if possible.
I’m following your guide to reinstalling without wiping the disk, but I don’t understand how to download CCC on the affected Mac 🤔 or should that be on a different Mac?
If so, how does that help me on the affected Mac?

You install CCC on the affected computer after installing MacOS to the new partition and booting into it. Just whatever you do, do not install macOS to your previous partition with all the old data. Then once you are inside it and using CCC you copy over the data from old partition onto the USB drive. Then use migration assistant, selecting the external drive, to transfer old data to new partition.

 

[Ens]

You install CCC on the affected computer after installing MacOS to the new partition and booting into it. Just whatever you do, do not install macOS to your previous partition with all the old data. Then once you are inside it and using CCC you copy over the data from old partition onto the USB drive. Then use migration assistant, selecting the external drive, to transfer old data to new partition.

Ah, gotcha!
I’m trying this but I’m already having an issue creating the partition.
I have 45Gb of free space left on my internal drive, is that enough to install a copy of MacOS on?
See attached images. The 1st image is after clicking Partition, there it says that the used space will be deleted.
The 3rd image is after clicking the + under the partition pie chart. Is that where I should add the partition? This won’t delete anything?

 

[neobow2]

Ah, gotcha!
I’m trying this but I’m already having an issue creating the partition.
I have 45Gb of free space left on my internal drive, is that enough to install a copy of MacOS on?
See attached images. The 1st image is after clicking Partition, there it says that the used space will be deleted.
The 3rd image is after clicking the + under the partition pie chart. Is that where I should add the partition? This won’t delete anything?

That should be enough to get macos installed. But that does me that you don't have enough storage to copy it into a new partition. You need to buy/use a 500 or 1tb external ssd or usb drive for when you copy the the old partition over

 

[Fishrrman]

Ens wrote:
"I have 45Gb of free space left on my internal drive, is that enough to install a copy of MacOS on?"

Maybe, maybe not.

As preposterous as it sounds, I recall reading elsewhere that you need about 60+gb of "free space" in which to do a Mac OS installation. Probably because things like "the sealed system volume" are first created in some kind of installer "work space", and then copied in toto to the actual sealed volume.

I could be completely wrong as to how this is done, and I welcome correction from others in-the-know...

 

[Ens]

That should be enough to get macos installed. But that does me that you don't have enough storage to copy it into a new partition. You need to buy/use a 500 or 1tb external ssd or usb drive for when you copy the the old partition over

Yep I have an external SSD ready to go for a copy of the old data.
But I have a feeling I’m not going to be able to partition, see attached image.
I’ve set the partition size to 35Gb, but it’s still telling me the old data will be deleted.
When I run First Aid to check for problems on the disk, it also says it has a problem unmounting one of the volumes.

 

[Ens]

Ens wrote:
"I have 45Gb of free space left on my internal drive, is that enough to install a copy of MacOS on?"

Maybe, maybe not.

As preposterous as it sounds, I recall reading elsewhere that you need about 60+gb of "free space" in which to do a Mac OS installation. Probably because things like "the sealed system volume" are first created in some kind of installer "work space", and then copied in toto to the actual sealed volume.

I could be completely wrong as to how this is done, and I welcome correction from others in-the-know...

I might be able to tell you soon enough, that’s if I can get the partitioning going

 

[Ens]

Scratch all that, I was in the wrong menu.

I clicked the + in the top bar the create a new volume (instead of a new partition).
But as @Fishrrman warned, 45.33 Gb isn’t enough for the install, it’s telling me I need an additional 5.45 Gb 🥲

 

[Fishrrman]

Ens --

If nothing else works, you could try this.

Back up whatever you have on the internal SSD.
Get it someplace other than the internal drive.
DO NOT PROCEED UNTIL YOU ARE BACKED UP. You have been warned.

Now...
We're going to NUKE the internal drive back to "moment zero" (moment zero is when you first took it out of the box, and pressed the power on button for the first time).

You need to be logged in to an administrative user account.
Go to system settings.
Enter into the search box "erase all content" -- this should show you how to get to the "erase all contents and settings" option.

When you get there, enter the password and sit back. It won't take long.

When done, you're going to see the initial setup application again.
That's because all your previous messin' with the Mini ... is gone.

So, assuming you have the important personal data backed up (time machine or cloned backup works for this), you can connect the backup and restore.

Or... start over completely.

One final suggestion:
Do not, let me repeat for clarity, DO NOT... install beta software as "your main OS".

If you want to play with OS developer betas (I do), install them onto an EXTERNAL DRIVE and then boot to that. Don't try to partition the internal SSD -- also may lead to unintended circumstances.