Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

neobow2

macrumors newbie
Original poster
Feb 24, 2025
3
0
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
 
Last edited:
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.
 
Last edited:
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.
 
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).
 
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
 
> 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. 🛠️
 
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.
 
  • Like
Reactions: IowaLynn
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.
 
> 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.
 
Last edited:
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.