Help needed to fix elderly neighbour's iMac booting up with panic(cpu 2) error

IpodTouchERM wrote:

The full drive is one of my queries, if you see from the picture above the Untitled drive is showing as only having 69.39GB used. It's only when I run First Aid on it or try to create an image that it then shows it's full. If I come out DU and back in it then shows 63.9GB used again. Is the full disk pic an anomaly of DU and a Red Herring?

When you created the disk image, did you by any chance, accidentally store the new disk image on the same internal disk that you were imaging? That could be like a snake trying to eat its own tail. I'm not sure whether Disk Utility would let you try that … but if it did, I could see how it wouldn't end well.

• As I mentioned, I'm not an expert with Apples, if I can't boot it up then how can I use a third party backup program?

How did you get into Disk Utility if you couldn't boot the system? You don't need to install those programs on the drive being backed up. If you are booting from an external drive and can install and run programs from it, that's all you need. You tell the backup program the source and destination when you run it.

• It's unlikely to be a RAM seated issue, it has sat in the same place for years without moving and she wouldn't have a clue how to access the RAM modules and tbh neither do I! I've had a look and there's a slot on the side under the CD-ROM drive which looks like an SDRAM slot with nothing in it, is that what you are referring to? Can't see any way of accessing the RAM modules from there.

I agree that it's unlikely to be a RAM issue, but if it is the model I'm thinking about, the instructions for installing RAM are here:

Install memory in an iMac - Apple Support

The "slot on the side which looks like a SDRAM [sic] slot with nothing in it" is not a RAM slot. It is a slot for a SD, SDHC, or SDXC flash memory card (like the ones used in many digital cameras). Useful for transferring pictures, and possibly for copying files off of the iMac, although I don't think you can boot from one of those cards.

At the moment all I really want is to get her Data backed up then I can worry about trying to restore the system or moving it to an external drive. Would all her Data be stored down the 'USR'DIR? Using DU I can navigate around the Directory structure ok. If the drive is actually full could it be failing as I'm trying to back it up to a 1TB backup? Could I just backup certain directories to get her data backed up?

Thanks again for your help.

Pretty much all of her data would be stored under her top-level user directory.

Let's say that her name was Sarah Smith, and that her account had the user name 'ssmith'.

• In the Finder, you could find her top-level directory by double-clicking on the hard drive icon, then on Users, then on ssmith.
• The Finder has a Go menu with a Home item, but you wouldn't use that, because you want her directory on the internal disk, not the home directory of the logged-in user on the external startup drive.
• In Terminal, her directory would be something like /Volumes/Macintosh\ HD/Users/ssmith/. You need to put the /Volumes/drive_name/ part at the beginning because /Users by itself refers to the current startup drive. Unix shells treat space characters as marking the end of an parameter, so you need to "escape" spaces by putting a backslash (\) character in front of them.
• A useful trick: In many cases, you can drag files and directories into Terminal to have the system type out filenames and directory names, complete with any required escape characters. So you could type "ls -l " (Unix directory command, followed by space) into Terminal and drag in an icon to complete the command.

On my Mac, I put some reference material into the top-level User Guides And Information folder, because it looked like a handy place to store that stuff, but I doubt that your neighbor has gone that far.

Since you can get into Disk Utility, you might want to click on the top lnternal line (the "ST31000528AS …" one) and check the S.M.A.R.T. status at the bottom of the first column.

If it is "Failing", that is further evidence (on the top of what First Aid told you) that the time to save data from her internal drive is now, while it is still possible. Replacing the internal hard drive on these iMacs is difficult … so if you find that the S.M.A.R.T status is "Failing" (or just don't trust the drive in general), I would suggest getting an external drive, installing the operating system on it, and using it as the startup drive (ejecting the internal drive whenever it appears and not relying on it to store data).

It doesn't make me comfortable that the internal drive shows as completely full and that its name is "Untitled". When you fill a hard drive to the absolute brim, it causes the system to become unbearably slow. (My internal hard drive has 63 GB out of 2 TB free, but it's like pulling eye teeth if something happens to cause my Mac to reboot from it rather than from my external FireWire 800 startup drive. Your neighbor's drive shows NOTHING free.) The "Untitled" name could be harmless (someone could have changed it to that), but since the default name is "Macintosh HD" and people usually pick custom names that are more interesting than "Untitled", this name strikes me as a potential indicator that something happened to the filesystem.)

Try running the Apple Diagnostics to see if any hardware issues are detected. The only useful diagnostic is one which produces an error code or one which freezes while testing. Unfortunately the diagnostics don't detect most drive failures or memory failures.

Unfortunately it looks this iMac is running a really old version of macOS which means you probably don't have access to Internet Recovery Mode.

Make sure all external devices are disconnected in case one of them is causing a problem.

Try booting into Safe Mode. I doubt this will work since it seems the boot process is failing very early.

You have two options to test this iMac. Install macOS to the external drive and see if the iMac will boot from the external drive. This will allow you to better assess this iMac since Recovery Mode is just too limited. If you can boot from an external drive with a full copy of macOS, then you can use DriveDx to check the health of the internal drive. Post the complete DriveDx text report here using the "Additional Text" icon which looks like a piece of paper. Just make sure to use Disk Utility to erase the external drive as GUID partition and MacOS Extended (Journaled). If you are booting to a macOS 10.6 to 10.10 installer, then you may instead need to partition & format the drive using the instructions in this article:

https://eshop.macsales.com/tech_center/formatting/Mac_Formatting_6-10_R3.pdf

If booting a macOS 10.11, 10.12, or 10.13 installer, the you just use the "Erase" tab in Disk Utility making sure to select the physical drive to erase.

The other option would be to create & boot a Knoppix USB stick so you can check the health of the internal hard drive. If Knoppix boots, then the basic hardware is functional. For an older iMac I would recommend using Knoppix v8.6.1, just make sure to get the DVD version which has "EN" in the name for ENglish. You can use the downloaded Knoppix .iso file as a source for Etcher (Mac/Windows/Linux).

Just Option Boot the Knoppix USB stick and select the orange icon labeled "EFI" from the Apple boot picker menu. While Knoppix is booting, the computer may appear frozen so make sure to give Knoppix lots of time to finish booting (the apparent freeze is due to EFI firmware issues related to video as Knoppix is unable to display anything early on in the boot process...plus it pauses for a short while to accept user input). If Knoppix boots to the desktop, click the "Start" menu and navigate to "System Tools --> GSmartControl". Within GSmartControl double-click the icon for the internal drive to access the drives health information. There is a "report" option which will give you a full text report of the health information for the drive....post that report here using the "Additional Text" icon which looks like a piece of paper.

Knoppix can also be used to recover data from the internal drive if necessary, but using macOS boot drive is best in if at all possible...especially if the recovered items will be used on another Mac. It can even be used to clone a failing hard drive using the correct utility.

If you want to check the memory, then you can use a bootable Memtest86 USB stick. I would first try the default Memtest86 settings, but if there are no errors or freezes, then adjust the Memtest86 CPU settings to "Round Robin" or "Sequential" since I have found these other CPU settings tend to cause a system freeze if the memory is faulty (usually occurs fairly quickly). You can use Etcher to make a bootable Memtest86 USB stick from the downloaded .img file as a source.

FYI, don't try to copy any data until you confirm the health of the hard drive. If the hard drive is failing, then the normal apps (even most data recovery apps) won't work since they cannot deal with the errors.

Another option to access the data if the hard drive is confirmed to be healthy....put the iMac into Target Disk Mode and connect it to another computer to access the data. This requires the proper cables & adapters and is best done when connected to another Mac.

Do not use Disk Utility to create an image of the boot drive even if the hard drive is healthy. Theoretically it should work, but many times it will fail. Better to just make an image of the home user folder located in the "Users" folder.

That error is related to some sort of network issue. Try connecting the iMac directly to the router using an Ethernet cable for a faster more reliable connection which bypasses hard to troubleshoot WiFi issues.

If you have access to another Mac from 2008 to 2015, then you can create & use a bootable macOS 10.11 USB installer:

Create a bootable installer for macOS - Apple Support

The "iMac11,2" on the panic screen seems to correspond to an iMac (21.5-inch, Mid 2010).

That machine had user-accessible RAM, and I suppose it is remotely possible that poorly-seated RAM could be causing crashes. Poorly seated RAM wouldn't explain why the internal drive is completely full (which may be the real culprit behind all of the filesystem issues). I'm just mentioning it for completeness.

You don't have to open the case to get to the RAM – there's a small access hatch. If you do pull and reseat the RAM, be careful not to break the plastic straps that you will probably have to use to unseat the RAM.

It might help to use a third-party backup program like Carbon Copy Cloner or SuperDuper!, instead of creating a disk image with Disk Utility. Maybe if you were just trying to back up data (not create a bootable backup), one of them would keep going in the face of errors, and tell you what files it couldn't copy afterwards?!?

Disk Utility is probably giving up completely on creating a disk image at the sign of the first error.

Servant of Cats wrote:

How did you get into Disk Utility if you couldn't boot the system?

I suppose you could be using Recovery mode. Snow Leopard (the original OS for mid-2010 iMacs) did not have Recovery mode, but someone could have upgraded that Mac to Lion (or later), which would have installed it.

Jeez-oh-Pete! I'm a patient guy, but at this point I think I'd consider this Mac a lost cause and get something else. Even a dirt cheap bargain basement Windows laptop would be better than the grief gotten from this thing.