2015 iMac Won't boot, internal ssd doesn't show in recovery mode

[gpspad]

My parents have a Late 2015 27" iMac with a 512gb internal ssd that was running OSX Monterey. I can get it to go to recovery mode just fine, but when I try to reinstall osx (which is osx sierra) it doesn't see the internal hard drive.

Using the terminal command in recovery mode I get this listing when I use diskutil list.....

I have a feeling this has something to do with the ssd being converted to APFS. There seems to be a lot of random disks showing in the list. I have seen videos on YouTube of people using the terminal command to clean up and manually reformat the ssd. i think that may be the problem here as the recovery portion is just fine.

Any suggestions on what commands to reformat the ssd so I can install a new osx on this?

Also I was trying to run it through an external ssd, I managed to get a CCC external running, but when i try to connect a second external ssd drive to it and install an new version of Monterey, it never sees the external ssd.

 

[FreakinEurekan]

Boot using Command-Option-R. Then it should install.

 

[DeltaMac]

Did the Monterey system have a problem?
I think you need to boot to a system newer than Sierra, as it likely does not see the existing drive, as the Sierra install may not see the drive at all, when a much newer system is installed.
It does concern me when the drive itself is not appearing in the diskutil terminal window.
You see only the Base System, which is not on your iMac at all--it is just the system used to boot your iMac, and is on Apple's remote server
I would suggest making a bootable USB installer for Monterey.
Boot with that bootable installer, THEN open Disk Utility. Do you see the existing drive then?

 

[FreakinEurekan]

Not seeing the volumes, etc on an APFS disk is expected with OS X Sierra's Disk Utility.

Booting with Command-Option-R will give Monterey disk utility, at which point you'll be able to verify (or if necessary, format) the disk & install Monterey.

 

[Fishrrman]

I can get you fixed up.

BUT... it's probably going to erase all the data on the internal SSD.
Is that drive backed up?

PRINT OUT this reply and refer to it as you work.

Here's what to do.
1. Boot to INTERNET recovery:
Command-OPTION-R
at boot

Press that key combo and HOLD IT DOWN as you press the power on button, and then KEEP HOLDING IT DOWN until you see the notice that internet recovery is in progress... the "spinning globe".

If the iMac connects via wifi, you'll need the wifi password.
ETHERNET IS BETTER for this job.

2. You will get to the internet utilities.
At this point, you could open the OS installer and TRY to install Monterey to see if the install will go through. No promises. It might work, or it might not.
What you do at this point is UP TO YOU.
I would try it first, and if it fails, go to step 3.

3. If you can't install Monterey "as things stand", you will have to erase the drive and "start fresh".
Get back to the internet utilities (reboot to Internet Recovery if you need to).
This time, choose disk utility.
VERY IMPORTANT STEP: go to the "view" menu and choose "show all devices".
You can't see the internal drive until you do this!

4. Look at "the list on the left". The topmost item should be the physical SSD inside.
Click on it to select it, then click "erase".
Erase to APFS, GUID partition format.
When the erase is done, quit disk utility and open the OS installer.

5. Start "clicking through". The iMac will reboot one or more times, and the screen will go dark for a minute or more with no other indication of activity. Just be patient.

6. When done, you should see the initial setup screen "choose your language".
IF YOU HAVE A BACKUP DRIVE, CONNECT IT NOW.
Start clicking through setup.
Setup assistant will ask if you wish to migrate data from another drive.
You need to "point the way" for setup assistant, and then give it time to "digest everything".
I would suggest that you migrate everything, and just let setup assistant go to work and do its job.

Good luck.

One possibility ... could the internal SSD have failed?
You'll find that out if you get to internet recovery, and disk utility can't "find it"...

 

[DeltaMac]

The OPs Late 2015 iMac should boot (with Internet Recovery) to the oldest macOS that still supports that model, which should be El Capitan, or maybe Sierra.
Neither of those are likely to see the Monterey drive correctly, and both are too old to have the option to "Show All Devices"
However, the list on the left in Disk Utility, even on those older MacOS, should show that there is an internal device, even if the volumes are not displayed. (The "Base System" is NOT an internal drive, and not helpful to troubleshoot)

I also suspect that the OPs internal SSD has failed, but best chance to see the drive will be when booting from a newer system, such as a Monterey installer USB drive (or at least High Sierra or newer)

 

[FreakinEurekan]

The OPs Late 2015 iMac should boot (with Internet Recovery) to the oldest macOS that still supports that model, which should be El Capitan, or maybe Sierra.

There are two ways to boot IR on a 2015 iMac. Command-Option-R will load the newest compatible version of macOS (Monterey). Command-Shift-Option-R will load the original version (El Capitan).

 

[DeltaMac]

Understood... But, the OP is apparently booting with Command-Shift-Option-R, and getting what appears to be the closest version that is still available, which the OP shows Sierra.
I suspect that the internal boot drive is bad, causing the recovery boot to default to the oldest system, as the current installed (recovery) system is (because of a likely damaged/dead boot drive) gone.

 

[FreakinEurekan]

Understood... But, the OP is apparently booting with Command-Shift-Option-R, and getting what appears to be the closest version that is still available, which the OP shows Sierra.
I suspect that the internal boot drive is bad, causing the recovery boot to default to the oldest system, as the current installed (recovery) system is (because of a likely damaged/dead boot drive) gone.

Certainly it's possible... but could just be the APFS formatting not being recognized by El Cap's Disk Utility.

If it's not showing up even when booted with Command-Option-R, then @DeltaMac has it - hardware failure.

 

[gpspad]

Thanks for all the replies

I can get you fixed up.

BUT... it's probably going to erase all the data on the internal SSD.
Is that drive backed up?

PRINT OUT this reply and refer to it as you work.

Here's what to do.
1. Boot to INTERNET recovery:
Command-OPTION-R
at boot

Press that key combo and HOLD IT DOWN as you press the power on button, and then KEEP HOLDING IT DOWN until you see the notice that internet recovery is in progress... the "spinning globe".

If the iMac connects via wifi, you'll need the wifi password.
ETHERNET IS BETTER for this job.

2. You will get to the internet utilities.
At this point, you could open the OS installer and TRY to install Monterey to see if the install will go through. No promises. It might work, or it might not.
What you do at this point is UP TO YOU.
I would try it first, and if it fails, go to step 3.

3. If you can't install Monterey "as things stand", you will have to erase the drive and "start fresh".
Get back to the internet utilities (reboot to Internet Recovery if you need to).
This time, choose disk utility.
VERY IMPORTANT STEP: go to the "view" menu and choose "show all devices".
You can't see the internal drive until you do this!

4. Look at "the list on the left". The topmost item should be the physical SSD inside.
Click on it to select it, then click "erase".
Erase to APFS, GUID partition format.
When the erase is done, quit disk utility and open the OS installer.

5. Start "clicking through". The iMac will reboot one or more times, and the screen will go dark for a minute or more with no other indication of activity. Just be patient.

6. When done, you should see the initial setup screen "choose your language".
IF YOU HAVE A BACKUP DRIVE, CONNECT IT NOW.
Start clicking through setup.
Setup assistant will ask if you wish to migrate data from another drive.
You need to "point the way" for setup assistant, and then give it time to "digest everything".
I would suggest that you migrate everything, and just let setup assistant go to work and do its job.

Good luck.

One possibility ... could the internal SSD have failed?
You'll find that out if you get to internet recovery, and disk utility can't "find it"...

Thanks for the detailed response, my parents just bought a 24" iMac, so I have a lot less pressure on me now to fix it. I would like to get it going again instead of just throwing it away.

I did create a Monterey boot-up disk and put it on a thumb drive with the latest Monterey on it. The internal ssd still doesnt show up to the installer boot-up with the thumb drive. Do you think it's worth trying those steps you outlined?

If I do the steps above, will I loose the ability to boot it from an external drive?

Thanks for the great entailed response, I just dont understand where the rescue portion lives and if the rescue partition working means the SSD is OK. I have actually learned a bunch from this.

 

[gpspad]

Certainly it's possible... but could just be the APFS formatting not being recognized by El Cap's Disk Utility.

If it's not showing up even when booted with Command-Option-R, then @DeltaMac has it - hardware failure.

As I just posted, my parents bought a 24" so the pressure was off of me to fix this. I was able to move all their data to the new machine, now Im just trying to save it from the landfill, even if it means some brain surgery and getting a new SSD. Im going to g through all the steps and post an update to maybe help the next person it happens to.

 

[gpspad]

So looking through the replies, my question is.....

Where does the boot drive live?

Can the rescue disk be OK and the main SSD be bad?

That part of this I'm not understanding.

 

[FreakinEurekan]

"Apple disk image media" and "OS X Base System" are virtual in RAM. They're not on any storage medium at all.

Totally possible that the SSD is bad.

 

[gpspad]

"Apple disk image media" and "OS X Base System" are virtual in RAM. They're not on any storage medium at all.

Totally possible that the SSD is bad.

Thanks for the reply, this has been a learning process on the recovery disk. I believe the disk must be bad because when I do the internet recovery and start diskutil, the boot disk shows up as an external disk.

I am just confused why the diskutil list command shows a bunch of 500gb partitions that don’t show up in diskdoctor. Booting from a Monterey boot up disk with instal program doesnt show the internal drive in disk doctor.

what are my disk replacement options?

any recommendations on an ifixit installation kit and buying a SSD for it?

I hate the idea of dumping this in a landfill, it was always a good machin.

 

[gpspad]

You know what Im a moron, I just looked through that "diskutil list" listing and I so wanted a sign life that the ssd didnt die I didnt notice the 512kb wasn't a 512gb, I didn't put two and two together. Add to the fact that I now know the rescue disk is in ram, I should have noticed that the 512 was in KB.

Sorry for wasting every ones time, its the first time i had a disk problem with one of the iMacs a reinstall didn't fix. I still hate the idea of just throwing this computer away.

 

[DeltaMac]

Your screenshots from post #14 are the same that you posted in your #1 post, which is from a Sierra boot.
Can you show the same set of screenshots, but from when you are booted to the Monterey USB boot drive.
One major difference will be in the Disk Utility. Monterey Disk Utility will have the choice to change the View option to "Show All Devices"

 

[Nguyen Duc Hieu]

You know what Im a moron, I just looked through that "diskutil list" listing and I so wanted a sign life that the ssd didnt die I didnt notice the 512kb wasn't a 512gb, I didn't put two and two together. Add to the fact that I now know the rescue disk is in ram, I should have noticed that the 512 was in KB.

Sorry for wasting every ones time, its the first time i had a disk problem with one of the iMacs a reinstall didn't fix. I still hate the idea of just throwing this computer away.

You don't need to throw the computer away.
Only the internal SSD is dead. Just use an external SSD to install Monterey on and boot from there. It'd better be an nVME blade in a USB enclosure, so when you (or later owner) decide to transfer it to internal, it will save you some time.

Following the guide of Fisherrman above, with a little adjustment like below:

Step 0. Plug in the blank external disk before powering up.
Step 4. Instead of looking for the internal disk (we suppose it was dead and not recognized by the iMac any more), just install Mac OS to the external disk.

 

[Fishrrman]

OP:

If you conclude that the internal SSD has failed, you can still boot and run the iMac using an EXTERNAL USB3 SSD.

It's cheap and easy to do -- will run only $60 or so for a 500gb drive.

Get either of these (I'd buy the cheaper one):

Crucial BX500 480GB 3D NAND SATA 2.5-Inch Internal SSD, up to 540MB/s - CT480BX500SSD1

Ever wonder why your phone responds faster than your computer? It's because your phone runs on flash memory. Add flash to your laptop or desktop computer with the Crucial BX500 SSD, the easiest way to get all the speed of a new computer without the price. Accelerate everything.

tinyurl.com

or

Crucial MX500 500GB 3D NAND SATA 2.5 Inch Internal SSD, up to 560MB/s - CT500MX500SSD1

Start your system in seconds store up to 4TB of data and upgrade with an SSD you can count on Join more and more people who are keeping their family videos travel photos music and important documents on an SSD and get the near-instant performance and lasting reliability that comes with solid stat...

tinyurl.com

Then get this:

SABRENT 2.5 Inch SATA to USB 3.0 Tool Free External Hard Drive Enclosure [Optimized for SSD, Support UASP SATA III] Black (EC-UASP)

SABRENT 2.5 Inch SATA to USB 3.0 Tool Free External Hard Drive Enclosure [Optimized for SSD, Support UASP SATA III] Black (EC-UASP)

tinyurl.com

Put the drive into the enclosure and boot to INTERNET recovery
Command-OPTION-R
... at boot

Then follow the instructions I posted above with ONE main exception:
When the installer asks WHERE you want to install, "point the way" to the external SSD and let the installer put a copy of Monterey onto it.

When done, you'll need to go to the startup disk preference pane and set the external drive to be "the new BOOT drive".

This will give you an external SSD that will boot and run at a respectable speed.
Not quite as fast as if it were installed internally, but "getting pretty close".
And a LOT LESS trouble than prying it open (at the risk of breaking something inside).
Good luck.

 

[AL2TEACH]

hate the idea of just throwing this computer away.

My 2015 works like a charm and I have no compelling reason to upgrade. I do like stage manager but...
Your problem is a fixable one and no need to toss it. What did you decide to do?
Pray tell, don't leave us hanging!!!!!

 

[Brian33]

Yeah, using same computer (still working but fingers crossed)... wondering what its sibling's fate is...

 

[gpspad]

My 2015 works like a charm and I have no compelling reason to upgrade. I do like stage manager but...
Your problem is a fixable one and no need to toss it. What did you decide to do?
Pray tell, don't leave us hanging!!!!!

My parents are doing fine with the M1 24" iMac, although they hate the screen and wish they had a 27" one like the 2015. But they are OK with the smaller screen and getting used to it when I explain to them that a studio display and mac mini or stdio will be in the $3,000 range. The M1 24" with a 512gb SSD cost them $1,000.

The plan right now is to take an old 512gb ssd I have an setup the old mac with Monterey and setup an account as john doe running from an external drive, and just keep it around as backup computer. It will be ready to go though.

I gotta ask my sister if she wants to spring for a 1tb ssd and wants it. Right now she has a 2012 mac mini with a 1tb ssd drive I installed inside of it, she needs a minimum of 1tb to store all the family photos. The mac mini is a sorta backup to all the iCloud photos. The problem with apples small drive size, is once you get a bigger drive, it's hard to go to a smaller one. :-(

 

[AL2TEACH]

M1 24" iMac, although they hate the screen

I can understand. Got my sister an iMac for Christmas to replace her 2013 27" iMac and she still hasn't replaced it yet lol. She says she's cleaning the machine out but I think it's the screen size and I can't blame her.

a studio display and mac mini or stdio will be in the $3,000 range.

Yep and that says to put it mildly lol eh nope for me.