iMac Boot Loop

[doogie89]

My Late 2014 iMac has been stuck in a boot loop. I keep getting the screen where it says "your computer restarted because of a problem press a key or wait a few seconds to starting up". I am also getting a screen that says "support.apple.com/mac/startup with a slash symbol. See the images below. I have reset the NVRAM and SMC. I have created a Mac OS Big Sur USB bootable drive. Whenever I boot into that, I can see the bootable drive. Upon selecting it, the computer attempts to reboot into it then goes right back to the error screen about my computer restarting because of a problem. I am also getting this same issue when attempting to load the internet recovery.

I did upgrade my hard drive from the fusion to a Samsung SSD a few years ago, so I don't have the recovery partition anymore. I'm somewhat at a loss of how I can fix this iMac. No internet recovery, no usb bootable installer working, no recovery partition. I am stuck in this boot loop.

 

[DeltaMac]

Big Sur?
Do you still have the patched USB installer that you used to install Big Sur in first place?
I suppose you used the Open Core method. You could still use that to reinstall Big Sur. That should get your iMac working again.

 

[doogie89]

Big Sur?
Do you still have the patched USB installer that you used to install Big Sur in first place?
I suppose you used the Open Core method. You could still use that to reinstall Big Sur. That should get your iMac working again.

I am currently running the latest version of Big Sur. I used this link to create a bootable USB installer with the latest download of Big Sur. I am able to view the USB as an option to boot when holding down "Option" at boot. When I select it, I see the apple logo with a loading bar, but then it just restarts to the same error message.

Create a bootable installer for macOS - Apple Support

You can use a USB flash drive or other secondary volume as a startup disk from which to install the Mac operating system.

support.apple.com

 

[Fishrrman]

Questions:
- Once you installed the SSD, did you "re-fuse" it with the internal HDD?
- If so, WHAT SIZE is the internal HDD?
- is it by any chance, 3tb?

2013 iMacs had a problem with the internal 3tb HDD drives -- prone to failure.
Apple had a recall on these for a while.
Of course, all done now.

It won't do internet recovery?
Command-OPTION-R
at boot?

 

[doogie89]

Questions:
- Once you installed the SSD, did you "re-fuse" it with the internal HDD?
- If so, WHAT SIZE is the internal HDD?
- is it by any chance, 3tb?

2013 iMacs had a problem with the internal 3tb HDD drives -- prone to failure.
Apple had a recall on these for a while.
Of course, all done now.

It won't do internet recovery?
Command-OPTION-R
at boot?

I have a 1TB Samsung SSD that replaced the stock 1TB HDD (which was fused with the 128GB SSD). So now I just have a 1TB Samsung SSD and a 128GB SSD that came with the computer, but not fused together. And yes, when I attempted the internet recovery, I was able to connect to wifi and it started the process of loading but then the computer just restarts and shows me the error screen I attached above. While resetting the NVRAM, I was able to get it to load the login screen (showing the user accounts), but then it immediately rebooted. To me that tells me that the hard drive has not failed yet.

Could it have anything to do with RAM failure?

 

[Bodhitree]

If it won’t let you start from a bootable USB drive, it sounds like a hardware failure. I thought all it needed to do was verify that the hardware is appropriate and you’d be good to go. Can you start in verbose mode?

What Is Verbose Mode Mac and How to Boot into It? [2024 Guide]

In this article, go through the details of verbose mode in Mac. Learn what verbose mode is and how to boot your device into it using easy and quick steps.

www.easeus.com

 

[DeltaMac]

You can't boot a 2013 iMac with Big Sur, or newer. That model does not boot to anything newer than macOS 10.15.7 (Catalina), unless you have a patched installer to use. The default bootable installer, using that Apple linked page, can't boot a 2013, unless it is Catalina or older.
If you did not do anything special (with a patched installer) to load and boot with Big Sur, then you don't have a 2013 iMac. Maybe it is a 2014, which should boot from Big Sur, natively.

Yes, you can get random reboots early in the boot process (including the login window), which might indicate a boot drive failure. Try booting to Internet Recovery , where you can test the drive with Disk Utility, and get a better idea about what problem you actually have.

 

[Fishrrman]

Is this a 27" iMac with replaceable RAM?
If so, has the RAM been changed from the factory configuration?
Do you still have the ORIGINAL Apple RAM?
If so, have you tried putting it back in (without any 3rd party RAM)?

 

[doogie89]

You can't boot a 2013 iMac with Big Sur, or newer. That model does not boot to anything newer than macOS 10.15.7 (Catalina), unless you have a patched installer to use. The default bootable installer, using that Apple linked page, can't boot a 2013, unless it is Catalina or older.
If you did not do anything special (with a patched installer) to load and boot with Big Sur, then you don't have a 2013 iMac. Maybe it is a 2014, which should boot from Big Sur, natively.

Yes, you can get random reboots early in the boot process (including the login window), which might indicate a boot drive failure. Try booting to Internet Recovery , where you can test the drive with Disk Utility, and get a better idea about what problem you actually have.

Sorry - it is a late 2014 model. It is currently running Mac OS Big Sur 11.7.1. When attempting to run the internet recovery, I get wifi connected and it starts to load but then reboots and goes back to the "Your computer restarted because of a problem" screen.

iMac (Retina 5K, 27-inch, Late 2014) - Technical Specifications - Apple Support

support.apple.com

 

[doogie89]

Is this a 27" iMac with replaceable RAM?
If so, has the RAM been changed from the factory configuration?
Do you still have the ORIGINAL Apple RAM?
If so, have you tried putting it back in (without any 3rd party RAM)?

I did upgrade it from 16GB stock RAM to 32GB crucial RAM. I do not have the stock RAM any longer. I upgraded this about 8 years ago when it was purchased and haven't had any issues before.

 

[DeltaMac]

When you try to boot to Internet Recovery, do you always get the spinning globe (and not the normal Apple icon)?
Try the alternate boot keys, one at a time to see if there is any difference. Either Option+Command+r or Shift+Option+Command+r. (Again, make sure that you see the spinning globe during boot)
Those choices should offer different versions of macOS to reinstall, but I think your main goal is to run Disk Utility to test (First Aid) the hard drive.
Keep in mind that if Internet Recovery boots to an old system (might boot to Yosemite), then the Disk Utility can't help you at all (the system, as well as Disk Utility, in that old system is too old to see the APFS volume, and probably won't see your Samsung drive at all because of that)
And, you best way forward will be to boot to a USB bootable installer. You might try making a new USB installer just to help troubleshooting - and Big Sur would be a great choice for that installer at this point.

 

[doogie89]

When you try to boot to Internet Recovery, do you always get the spinning globe (and not the normal Apple icon)?
Try the alternate boot keys, one at a time to see if there is any difference. Either Option+Command+r or Shift+Option+Command+r. (Again, make sure that you see the spinning globe during boot)
Those choices should offer different versions of macOS to reinstall, but I think your main goal is to run Disk Utility to test (First Aid) the hard drive.
Keep in mind that if Internet Recovery boots to an old system (might boot to Yosemite), then the Disk Utility can't help you at all (the system, as well as Disk Utility, in that old system is too old to see the APFS volume, and probably won't see your Samsung drive at all because of that)
And, you best way forward will be to boot to a USB bootable installer. You might try making a new USB installer just to help troubleshooting - and Big Sur would be a great choice for that installer at this point.

I do get to the internet recovery screen with both methods and after about 8 minutes of loading, the computer reboots and then crashes to the error screen in my first post. I also get the same issue with a USB installer with Big Sur preloaded.

 

[Fishrrman]

Replace the RAM.

Or, remove 1 DIMM and see if it runs without crashing that way.

If it DOES crash, replace the DIMM with the OTHER DIMM and try it that way.

 

[doogie89]

Replace the RAM.

Or, remove 1 DIMM and see if it runs without crashing that way.

If it DOES crash, replace the DIMM with the OTHER DIMM and try it that way.

I pulled all of the RAM out and attempted to boot with one at a time and it still crashes out.

 

[Sun Baked]

Does it run long enough to boot into single user mode?

Hold down command-s on boot until text appears.

Run "fsck -fy"

If you have errors, run it again, until it has no errors, or the same ones.

"reboot" (to exit and reboot)

 

[Nguyen Duc Hieu]

I pulled all of the RAM out and attempted to boot with one at a time and it still crashes out.

I don't think you should invest more time to this iMac.
It's clearly a failing GPU, which is soldered to the logicboard.
A thorough internal cleaning and rework of this GPU chip may help, but with very low probability.
The cost may exceed your budget, and even in a successful case, chances for it to fail again in the future is high.

 

[doogie89]

Does it run long enough to boot into single user mode?

Hold down command-s on boot until text appears.

Run "fsck -fy"

If you have errors, run it again, until it has no errors, or the same ones.

"reboot" (to exit and reboot)

I can stay in this mode all day. Not sure what all of it means. I tried the fsck -fy but all I get is “error: container /dev/rdisk2 is mounted, repairs in a mounted container is not supported yet”

 

[TheRealDGD]

Hi, this thread went dead, nobody said if there was a solution found. My issue is exactly the same as yours and I tried exactly the same things as everyone on this thread has mentioned and I still cannot get past that screen. What did you eventually end up doing? I have a mid2015 Macbook Pro. Were you able to get your data off your internal hard drive? Hope you found a solution and can provide a reply. Thanks.