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ddublu

macrumors 65816
Original poster
Jun 26, 2011
1,370
75
I have a 6-year-old iMac that has been humming along as my wife and kid's computer. Yesterday, it all but locked up with the spinning beachball. I rebooted and tried safe mode. As it booted up and showed the progress bar, it would get at the very end and then it shut down.

- I've reset NVRAM
- booted into Recovery Mode and ran disk utility - (got file system verify or repair failed - -69845 error)
- booted into internet Recovery Mode where it showed progress but then went to a black screen with an ! in a triangle showing -2003F

Are there any other suggestions for getting into this computer?
 
21" or 27"?
WHAT KIND of DRIVE is inside?
- platter-based?
- fusion?
- SSD?

Could be drive failure -- software corruption (filing system, etc.) or a hardware failure (more serious).
 
21" or 27"?
WHAT KIND of DRIVE is inside?
- platter-based?
- fusion?
- SSD?

Could be drive failure -- software corruption (filing system, etc.) or a hardware failure (more serious).

Sorry. 3TB Fusion drive. 27" Retina.
 
As I recall, the 2013/2014 iMacs with a 3tb fusion drive had a bad run of Seagate 3tb HDD's in them -- many premature failures.

Apple used to have a free replacement program for these drives, but that's almost certainly ended by now. You could always ask at a brick-n-mortar Apple Store if there's one close by.

That's my GUESS as to what you have -- a failed HDD portion of the fusion drive.

I wouldn't put another platter-based drive in there (if you choose to open it up). I'd put in an SSD instead, 1tb or 2tb.

Another course of action:
Leave the dead 3tb drive "dead, but inside".
Continue to boot from the 128gb SSD portion of the fusion drive.
Get an EXTERNAL drive for extra storage -- again, I'd suggest a 1tb or 2tb USB3 SSD.
 
As I recall, the 2013/2014 iMacs with a 3tb fusion drive had a bad run of Seagate 3tb HDD's in them -- many premature failures.

Apple used to have a free replacement program for these drives, but that's almost certainly ended by now. You could always ask at a brick-n-mortar Apple Store if there's one close by.

That's my GUESS as to what you have -- a failed HDD portion of the fusion drive.

I wouldn't put another platter-based drive in there (if you choose to open it up). I'd put in an SSD instead, 1tb or 2tb.

Another course of action:
Leave the dead 3tb drive "dead, but inside".
Continue to boot from the 128gb SSD portion of the fusion drive.
Get an EXTERNAL drive for extra storage -- again, I'd suggest a 1tb or 2tb USB3 SSD.


Thanks. Is the data on that drive toast? I'm due for a new editing iMac so I am taking my current machine and replacing the one that's having the problems with it and grabbed a new workhorse.
 
"Is the data on that drive toast?"

Will the drive mount AT ALL?
Or does it fail to boot 100% of the time?

With a fusion drive, you CANNOT just remove one "portion" of the drive and get data from it, because the two drives are fused together with software. Data recovery on "one removed drive" will be essentially impossible, because of the way fusion seems to work.

Having said that...
What I would do:

First thing, I'd try to boot FROM AN EXTERNAL BOOTABLE DRIVE.
Just because the internal fusion drive won't BOOT, doesn't mean it won't mount on the desktop if the computer is booted from another source.
We have to try that before going further.

You said that you cannot even boot to internet recovery?
Makes me wonder if there are other things wrong, as well.

Do you have access to another Mac, at home or at work?

Finally, do you keep a backup?
(if not, you have just discovered WHY you probably needed to do so...)
 
"Is the data on that drive toast?"

Will the drive mount AT ALL?
Or does it fail to boot 100% of the time?

With a fusion drive, you CANNOT just remove one "portion" of the drive and get data from it, because the two drives are fused together with software. Data recovery on "one removed drive" will be essentially impossible, because of the way fusion seems to work.

Having said that...
What I would do:

First thing, I'd try to boot FROM AN EXTERNAL BOOTABLE DRIVE.
Just because the internal fusion drive won't BOOT, doesn't mean it won't mount on the desktop if the computer is booted from another source.
We have to try that before going further.

You said that you cannot even boot to internet recovery?
Makes me wonder if there are other things wrong, as well.

Do you have access to another Mac, at home or at work?

Finally, do you keep a backup?
(if not, you have just discovered WHY you probably needed to do so...)

What's weird is that when I run disk utility on it, it finds the error and unmounts the disk and then I can't ever get it to mount back. Tried booting into safe mode and the progress bar appeared to get to 100% but then the computer just shuts down.

I've never booted up to an external drive. Just plug it in and boot up holding down the option key?

I do have backups (I use CrashPlan for my business and home computers) so the data isn't a worry. I also have another iMac and a MacBook Pro. What were you thinking re: "access to another Mac?"
 
What I think you ought to try is putting together an external drive with a bootable copy of the OS on it.

It could be a spare hard drive, SSD, USB flash drive, etc.

Hook the drive up to one of your OTHER Macs.

Now, either install a fresh copy of the OS onto it, or, you could use CarbonCopyCloner (which is FREE to download and use for 30 days) to clone over the OS from your MacBook or other iMac.

You can do a "test boot" on one of the other Macs to know the drive is bootable.
THEN... connect it to the problem iMac and see if it can boot that way.
If it CAN boot that way, perhaps you can get the internal drive mounted on the desktop long enough to get whatever you want off of it.

From that point, you can decide what to do next.

SINCE YOU SAID YOU HAVE A BACKUP...
If it IS a problem with the internal 3tb HDD, the next step may be to replace it, or just leave it in place and boot from the 128gb SSD portion of the fusion drive and use the Mac that way.

If it was me
and
If I determined the internal 3tb drive was bad
and
If I could then use disk utility to erase the SSD and start fresh (using it as a standalone SSD)
then
I would just leave the 3tb drive "dead in place", boot from the SSD, and use external storage to supplement the SSD.

That's how I would do it.
Others will give you different advice.
 
What I think you ought to try is putting together an external drive with a bootable copy of the OS on it.

It could be a spare hard drive, SSD, USB flash drive, etc.

Hook the drive up to one of your OTHER Macs.

Now, either install a fresh copy of the OS onto it, or, you could use CarbonCopyCloner (which is FREE to download and use for 30 days) to clone over the OS from your MacBook or other iMac.

You can do a "test boot" on one of the other Macs to know the drive is bootable.
THEN... connect it to the problem iMac and see if it can boot that way.
If it CAN boot that way, perhaps you can get the internal drive mounted on the desktop long enough to get whatever you want off of it.

From that point, you can decide what to do next.

SINCE YOU SAID YOU HAVE A BACKUP...
If it IS a problem with the internal 3tb HDD, the next step may be to replace it, or just leave it in place and boot from the 128gb SSD portion of the fusion drive and use the Mac that way.

If it was me
and
If I determined the internal 3tb drive was bad
and
If I could then use disk utility to erase the SSD and start fresh (using it as a standalone SSD)
then
I would just leave the 3tb drive "dead in place", boot from the SSD, and use external storage to supplement the SSD.

That's how I would do it.
Others will give you different advice.

Ok, I finally had a chance to get to this. I formatted an external SSD drive and put Catalina on it. Option power on and it starts up and appeared to be installing. MacOS Recovery shows up, I select install macOS, it then lets me choose the disk. I select the external drive but it's greyed out and says it's locked. I took that disk to my MBP and "get info.' Made sure all permissions were read and write and unlocked the lock. Restarted iMac again and the same exact scenario except this time it shows a second external drive. Still showing the first with the disk is locked and the second drive greyed out and it says it's not formatted for APFS. I selected the iMac drive just to see if it may work. I get an error about 20 secs after installation started saying "an internal error occurred while preflighting your volume for APFS conversion." Any suggestions? Do you think it would let me just erase the iMac drive? Would that potentially correct any issues on the drive? I am pretty confident that everything of any importance is off of it.
 
Leave the dead 3tb drive "dead, but inside".
Continue to boot from the 128gb SSD portion of the fusion drive.
Get an EXTERNAL drive for extra storage -- again, I'd suggest a 1tb or 2tb USB3 SSD.


That! Just unplug the spinner. I think you need a terminal command to sever the Fusion so the internal SSD is a stand alone drive... I did.
 
Can you help me with the terminal command? I am about to wipe this iMac and can get $650 for trade in with a bootable iMac vs. non so need this to happen..haha!
 
If one portion of the internal fusion drive (the HDD?) has suffered a hardware failure, you're not going to be able to mount it to "wipe" it.

It's going to have to go "as is".

You -might- be able to mount the other portion (the SSD?), and wipe that.
 
If one portion of the internal fusion drive (the HDD?) has suffered a hardware failure, you're not going to be able to mount it to "wipe" it.

It's going to have to go "as is".

You -might- be able to mount the other portion (the SSD?), and wipe that.
I can't even download Catalina on my iMac (that's running Big Sur) to put it onto a bootable disk...what am I missing?
 
"I can't even download Catalina on my iMac (that's running Big Sur) to put it onto a bootable disk...what am I missing?"

You've gotten yourself into a real pickle.
Hard to diagnose when one is not "sitting in front of the machine".

My advice is:
Either send it in for trade "as it is"
or
If you can't do that, put it into the closet for now.

What I would do if the computer was in my hands:
1. I'd boot from an EXTERNAL boot drive
2. I'd then erase one or both internal drives
3. I'd install a clean copy of ANY OS that would install onto whichever drive was working.
and then...
4. I'd let it go like that.
 
"I can't even download Catalina on my iMac (that's running Big Sur) to put it onto a bootable disk...what am I missing?"

You've gotten yourself into a real pickle.
Hard to diagnose when one is not "sitting in front of the machine".

My advice is:
Either send it in for trade "as it is"
or
If you can't do that, put it into the closet for now.

What I would do if the computer was in my hands:
1. I'd boot from an EXTERNAL boot drive
2. I'd then erase one or both internal drives
3. I'd install a clean copy of ANY OS that would install onto whichever drive was working.
and then...
4. I'd let it go like that.

Can I put big sur on an external drive and use that to boot up the old iMac even though it wasnt running big sur?
 
IF I were you (I realize I'm not), I'd FORGET ABOUT Big Sur and get any OS onto it that will boot it.
 
IF I were you (I realize I'm not), I'd FORGET ABOUT Big Sur and get any OS onto it that will boot it.
I am not concerned about which OS I use, I just want to use one that allows it to create the boot disk. On my iMac, where I am creating the boot disk, it won't let me download anything BUT Big Sur since I have Big Sur on my iMac. Pretty sure Catalina sits on the dysfunctional iMac.
 
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