Problems installing Monterey on 2015 iMac

[Speed38]

I am trying to install the latest version of Monterey on my 2015 iMac, which is booted from an External OWC SSD running Big Sur.

Monterey downloaded and was proceeding through the normal, multiple restarts when I got the screen pictured below.

Knowing that sometimes these things resolve themselves, I let the computer restart three times, but each time it delivered the same warning so I shut it down manually after the third one.

Any suggestions? I have a good TM backup (two in fact).

I am guessing the advice will be to restart in Recovery Mode, erase the SSD, reinstall Monterey and then use Migration Assistant…but I will wait to see what feedback wiser users may provide.

 

[Fishrrman]

Can you boot the iMac from the INTERNAL drive?

 

[Speed38]

Thank goodness, I can. With that knowledge in hand, what would you suggest???

 

[Fishrrman]

"Thank goodness, I can. With that knowledge in hand, what would you suggest???"

When you boot from the internal drive, does the EXTERNAL SSD (the one you normally boot from) show up on the desktop?
Can you access all your data files?

With that said:
Do you have a backup of the SSD?

Answer and we'll go further.

 

[Speed38]

Sorry for the delay; just got home.

Yes, the external OWC SSD Big Sur shows on the desktop.
With that OWC SSD mounted...
I launched Disk Utility and ran First Aid on Big Sur volumes, and it passed.
I then ran First Aid on Apple APFS Media and that took about 30', returning hundreds of this line:
error: Cross Check : Mismatch between extentref entry reference count (0) and calculated fsroot entry reference count (1) for extent (104979225 + 4)
But, at the end, it too got the green check mark and an OK.

Not entirely sure what you mean when you say "Can you access all your data files?
I am going to guess you mean that if I go to the external Big Sur SSD, do all my files and folders appear to be in there...and the answer is yes.

And, finally, yes. I have two current TM backups.

Standing by and continuing to be most appreciative of your help.

 

[Fishrrman]

My next suggestion would be...
Get booted from the INTERNAL drive...
Try the upgrade to Monterey again.
But... "aim it" at the external SSD (again).

See if it will go through this time.
No promises.
If that doesn't work, there'll be more suggestions.

 

[Speed38]

OK. Downloading it again now. Will report back tomorrow.

 

[Speed38]

07:42 & reporting back.

No joy. A reinstall of Monterey produced the same, "Your computer restarted because of a problem".

On hold for your next suggestion.

 

[Speed38]

Just to wrap up this thread, I admit defeat and am throwing in the towel.
I attached the OWC SSD to my MacBook Pro: (Retina, Mid 2012), macOS 10.15.7 (10.15.7 is the last macOS this MB Pro can handle).
I erased the OWC SSD.
I installed Catalina 10.15.7 on that OWC SSD.
I booted the MB Pro from the OWC SSD & everything worked just fine.
I attached the OWC SSD to the iMac and successfully booted the iMac from it.
So...I can boot the iMac from the OWC SSD using Catalina, but when I install Monterey on that same OWC SSD and try to boot the iMac from it, I get the "Your computer restarted because of a problem".

 

[J.Gallardo]

I believe Monterey can only be started from external disk IF internal disk is in Monterey also. Monterey needs something special at start up, and it resides in internal hardware.
(I don’t remember where did I find this info, but I’m sure because I was planning to keep my iMac in Mojave with external in Monterey, and is a no no. I changed my mind and understood I could upgrade internal to Monterey and keep Mojave in external, which is possible).

 

[Fishrrman]

"I believe Monterey can only be started from external disk IF internal disk is in Monterey also."

NO.
Absolutely not the case.

I have a 2018 Mini with Mojave as the internally-installed OS.

I have installed Monterey on an external SSD, and can boot and run from it with no problems at all.

 

[Speed38]

In my case, the internal HD of the iMac in question is indeed running Monterey.

I have posted this problem on several Mac forums and nobody has been able to come up with an answer.

 

[Speed38]

On the Apple Support Forum I found this:

I ran into the same issue and contacted OWC to see if they had a firmware update available for my SSD. Talking to support, they said that it isn't the SSD that requires the firmware update, but the MacBook Pro itself, which requires an EFI update that won't be installed unless there's an Apple SSD installed. They recommended that I reinstall the original Apple SSD, then install Monterey to get the EFI update, then replace the Apple SSD with the OWC SSD, and upgrade from Big Sur 11.6.1 to Monterey. According to OWC, they've tested this fix in their lab and it works. (We'll see.)

I checked my firmware and it’s - System Firmware Version: 447.60.3.0.0

I also wrote OWC for help, outlining my problem.

 

[Speed38]

Sunday...and I have not had the courtesy of a response from OWC. So much for customer support.

 

[bw44]

Just to wrap up this thread, I admit defeat and am throwing in the towel.
I attached the OWC SSD to my MacBook Pro: (Retina, Mid 2012), macOS 10.15.7 (10.15.7 is the last macOS this MB Pro can handle).
I erased the OWC SSD.
I installed Catalina 10.15.7 on that OWC SSD.
I booted the MB Pro from the OWC SSD & everything worked just fine.
I attached the OWC SSD to the iMac and successfully booted the iMac from it.
So...I can boot the iMac from the OWC SSD using Catalina, but when I install Monterey on that same OWC SSD and try to boot the iMac from it, I get the "Your computer restarted because of a problem".

Sorry to post to your thread, but I have an even more basic question that you might be able to answer: I have an early 2015 MBP with only the built-in HD. Somewhere I got the impression when Monterey came out that if you upgraded you wouldn’t be able to revert to Big Sur. Was this only a problem for the new M1 macs, or is it the case for my old MBP??

Thanks for any advice!

 

[Speed38]

It can be done and here are instructions on how to do so:

How to Downgrade from macOS Monterey to Big Sur

If you’ve updated your macOS to Monterey but want to know how to revert to a previous macOS, we have everything you need to know.

mackeeper.com

 

[bw44]

It can be done and here are instructions on how to do so:

How to Downgrade from macOS Monterey to Big Sur

If you’ve updated your macOS to Monterey but want to know how to revert to a previous macOS, we have everything you need to know.

mackeeper.com

Many thanks for this! Hopefully I won’t need it.

 

[Speed38]

Threads not dead...yet. OWC finally piped up. Their support is super busy and they are getting back to me but slowly.
Here are my exchanges with them so far:

22 December - from OWC:
Looking into this further, the firmware is updated properly on the computer, however let me take a look at the information a little more closely. Can you send me a copy of your System Report? To do this, go to the Apple logo in the upper left hand corner and select About This Mac. From there click on System Report. Once opened, click on File and select Save. Please be sure to save them as a .spx file.

23 December - to OWC:
The iMac has been problem free, running Big Sur, booted from the external OWC SSD, ever since Big Sur came out last year.

My first effort to install Monterey was to run Software Update from Sys Prefs while booted to Big Sur and that failed dismally.

I then booted up in Recovery Mode, erased the OWC SSD, formatted it at APFS, then installed Monterey from Recovery Mode.

Again, ended up with the multi-language alert.

23 December - from OWC:
Thank you for sending that over. I would like to narrow down the issue a bit further with you. Have you by chance tried installing Big Sur to the SSD at all? This is the OS before OS 12 Monterey, however I would like to see if it allows you to "step up" with the OS updates and if that provides better results.

23 December - to OWC:
The iMac has been problem free, running Big Sur, booted from the external OWC SSD, ever since Big Sur came out last year.

My first effort to install Monterey was to run Software Update from Sys Prefs while booted to Big Sur and that failed dismally.

I then booted up in Recovery Mode, erased the OWC SSD, formatted it at APFS, then installed Monterey from Recovery Mode.

Again, ended up with the multi-language alert.

28 December - from OWC:

Thank you for the message. Looking into this further, the next step here that I would recommend is booting up the computer using Command R. From there, go up to the Utilities option at the top of the screen and select Startup Security Utility. Once there, there should be an option to allow booting from external media. You will want to make sure that option is checked. With OS Big Sur and Monterey, they will not auto allow you to boot from them externally, however you can adjust that with the method above.

28 December - to OWC:
I know you folks are busy and I am grateful that you have not abandoned me.

When I followed your instructions, above, I was not presented with an option to allow booting from external media.

Instead I got: Startup Security Utility window with one choice only - Firmware password protection is off. Turn on a firmware password to prevent this computer from starting up from a different hard disk, CD, or DVD without the password.

I strongly suspect that some time ago, when I first began booting from that external OWD SSD, I did just what you suggested so that I would indeed be able to boot from the external HD.

 

[Sandman824]

Threads not dead...yet. OWC finally piped up. Their support is super busy and they are getting back to me but slowly.
Here are my exchanges with them so far:

22 December - from OWC:
Looking into this further, the firmware is updated properly on the computer, however let me take a look at the information a little more closely. Can you send me a copy of your System Report? To do this, go to the Apple logo in the upper left hand corner and select About This Mac. From there click on System Report. Once opened, click on File and select Save. Please be sure to save them as a .spx file.

23 December - to OWC:
The iMac has been problem free, running Big Sur, booted from the external OWC SSD, ever since Big Sur came out last year.

My first effort to install Monterey was to run Software Update from Sys Prefs while booted to Big Sur and that failed dismally.

I then booted up in Recovery Mode, erased the OWC SSD, formatted it at APFS, then installed Monterey from Recovery Mode.

Again, ended up with the multi-language alert.

23 December - from OWC:
Thank you for sending that over. I would like to narrow down the issue a bit further with you. Have you by chance tried installing Big Sur to the SSD at all? This is the OS before OS 12 Monterey, however I would like to see if it allows you to "step up" with the OS updates and if that provides better results.

23 December - to OWC:
The iMac has been problem free, running Big Sur, booted from the external OWC SSD, ever since Big Sur came out last year.

My first effort to install Monterey was to run Software Update from Sys Prefs while booted to Big Sur and that failed dismally.

I then booted up in Recovery Mode, erased the OWC SSD, formatted it at APFS, then installed Monterey from Recovery Mode.

Again, ended up with the multi-language alert.

28 December - from OWC:

Thank you for the message. Looking into this further, the next step here that I would recommend is booting up the computer using Command R. From there, go up to the Utilities option at the top of the screen and select Startup Security Utility. Once there, there should be an option to allow booting from external media. You will want to make sure that option is checked. With OS Big Sur and Monterey, they will not auto allow you to boot from them externally, however you can adjust that with the method above.

28 December - to OWC:
I know you folks are busy and I am grateful that you have not abandoned me.

When I followed your instructions, above, I was not presented with an option to allow booting from external media.

Instead I got: Startup Security Utility window with one choice only - Firmware password protection is off. Turn on a firmware password to prevent this computer from starting up from a different hard disk, CD, or DVD without the password.

I strongly suspect that some time ago, when I first began booting from that external OWD SSD, I did just what you suggested so that I would indeed be able to boot from the external HD.

I have a 2015 iMac and am having the exactly same problem. It somehow forced me to install monterey on my internal fusion drive which is working fine, but no amount of fussing allows me to install it or boot off my external ssd. Even tried a different case as I read somewhere to not avail, failed during migration stage.

I think I read somewhere that the startup security utility is for M1 macs only, not available on intel macs and I can't find it. Keep me posted if something works, for now I'm going to have to abandon my external ssd as boot and use as backup only.

 

[Speed38]

I have a 2015 iMac and am having the exactly same problem. It somehow forced me to install monterey on my internal fusion drive which is working fine, but no amount of fussing allows me to install it or boot off my external ssd. Even tried a different case as I read somewhere to not avail, failed during migration stage.

I think I read somewhere that the startup security utility is for M1 macs only, not available on intel macs and I can't find it. Keep me posted if something works, for now I'm going to have to abandon my external ssd as boot and use as backup only.

Will do so. I have this thread bookmarked in my Reading List on Safari and won't delete it until the problem is solved or OWC confirms that it is simply not possible.

 

[Speed38]

P R O B L E M S O L V E D !!!
Some Level 10 dude, named rkaufman, on the Apple Support site came up with the answer.
Just follow the instructions at this website:

How to Install macOS Monterey on External Hard Drive [4 Steps]

By installing macOS Monterey on an external hard drive, you can keep your main operating system intact and switch between them with ease.

www.macgasm.net

Here are the steps.
The problem was, I believe, that my external SSD was formatted as APFS, whereas the instructions at the website say to - Give the external hard drive a suitable name and select “Mac OS Extended (Journaled)” as the drive’s format and “GUID Partition Map” as the drive’s partition scheme. Who would have thought it?


• Connect the external hard drive to your Mac.
• Launch Disk Utility (located in Applications -> Utilities).
• Click View and choose the Show all devices option.
• Select your external hard drive (not just a single partition).
• Click Erase.
• Give the external hard drive a suitable name and select “Mac OS Extended (Journaled)” as the drive’s format and “GUID Partition Map” as the drive’s partition scheme.
• Click Erase and wait for Disk Utility to prepare your external drive for you.
• Launch the App Store on your Mac.
• Click the search bar, type in “macOS Monterey,” and hit Return.
• Select the search result named “macOS Monterey.”
• Click the Get button and wait for the macOS Monterey installer to download.
• Open Finder.
• Go to Applications.
• Launch the “Install macOS Monterey” app.
• Click Continue and then Agree.
• When you arrive on the drive selection screen, click Show All Disks.
• Select your external hard drive and click Continue.
• Select a user to set as the owner of the new volume and optionally copy the user’s account settings.
• Click Install to proceed.