Use of a Windows Diagnostic Tool on my iMac HD by a Technician

To add onto what others have said...

"ST1000DM003" indicates that this HDD is an Apple re-branded Seagate drive. The Linux HW project's collated drive statistics indicate that the stats for this model are:

• Samples - 81;
• Avg days / sample - 800;
• Avg errors / sample - 55;
• Avg MTBF in years - 1.87

The project includes large scale data from Google, Backblaze and Acronis.

In other words, this HDD may be prone to failures - which the ridiculous power on count from Crystal Disks may indicate the reason for - a poor disk controller that powers the disk on and off too often.

Consider upgrading to a SSD. Your HDD is likely failing.

I'm a bit late here, but I will try to help clarify a few things.

The tech appeared to have removed the Apple hard drive when they ran the Crystal Disk Info report since the Interface listed in the report is "UASP (Serial ATA)". The "UASP" part is a special USB protocol which indicates the hard drive was connected externally using USB to a Windows' PC.

The hard drive in that Crystal Disk Info report looks healthy although the complete report is not shown. With almost 33K power on hours the hard drive possibly has about 40%-50% life left regarding only the Power On Hours (the report is showing more like 37% worn with 63% remaining), but most hard drives these days rarely make it to 90K Power On Hours even under ideal circumstances....an iMac is far from ideal circumstances. As for someone mentioning the higher failure rate for Seagate hard drives, that was certainly true for many years starting around 2011 and lasting for about seven years, but they appear to be holding up better these days (I have even started using them again).

DriveDx (free trial period) can retrieve the health information of hard drives & SSDs which is the nicest looking & easiest to use macOS app of this type. DriveDx does a good job of analyzing & summarizing the health of a hard drive, but no apps are able to correctly summarize the health of an SSD....an SSD's health must be manually interpreted each time DriveDx notes any changes in an SSD's health information.

I would actually be interested in seeing the complete DriveDx text report for both the internal hard drive and SSD. Post the complete DriveDx text report here using the "Additional Text" icon which looks like a piece of paper on the forum editing toolbar.

I'm also curious about the memory as well since one of the Kernel Panics mentioned the memory changed after some memory was released. This could be due to a software issue (usually third party), or from bad memory. You can create and use a bootable MemTest86 USB stick to perform a longer more thorough memory test than the Apple Diagnostic performs. Make sure to only use the default MemTest86 settings since modified MemTest86 settings will unfortunately cause MemTest86 to freeze on the 2017+ Mac. You can use the downloaded MemTest86 .img file as a source for Etcher (Mac, Windows, Linux) to create the bootable MemTest86 USB stick.

The only way, unless I'm missing something, would be if the tech connected the hard drive to a Windows system which if the iMac was disassembled was probably what was done. As you say, CrystalDiskInfo is a Windows-only utility. Without knowing what else the tech might have done with the drive, I can't say that it's impossible that he/she caused a problem with the drive, but I don't think CrystalDiskInfo itself would have done that.

There are a number of reasons beyond the hard drive that your mac might be experiencing constant crashes, but if you erased the drive and reinstalled macOS from scratch and it's crashing just with the base OS, then it's likely to be a hardware failure of some sort, such as bad RAM or a failing processor. But given the number of errors that the disk utility reported - note what to me seems a high rate of read errors and uncorrectable errors - a failing hard drive would be my first suspicion. That the utility reports "Good" as the health status may just be the S.M.A.R.T. status and not actually a verification that the drive is not malfunctioning.

Regards.

lifewebb wrote:

varjak paw wrote:

The only way, unless I'm missing something, would be if the tech connected the hard drive to a Windows system which if the iMac was disassembled was probably what was done. As you say, CrystalDiskInfo is a Windows-only utility. Without knowing what else the tech might have done with the drive, I can't say that it's impossible that he/she caused a problem with the drive, but I don't think CrystalDiskInfo itself would have done that.

Thanks, but how could a Windows software be applied to an Apple HD? Did he erase the whole thing - nothing Apple left on it and then format it to be used by Windows in order to use the Windows software? Then erase again and install OS Sonoma from one of his hard drives? Because it definitely did not come from Apple directly as it was not up to date. I have checked Sonoma version Release dates and other software like Image Capture. I got an old version of Image Capture which does not work properly! And the latest version of Sonoma was not installed, I had to download it myself.

I think that is what must have been done. Since there are Mac compatible softwares to do the same diagnostic, I am just astonished that the HD has been 'fiddled' with in this way and it has generated mistrust about a change being made to the HD and some kind of 'residue' of formatting being left behind, messing with the operating system and with apps. Chrome is not behaving normally now either, for instance.

He would have removed the drive and connected it to a Windows system via a SATA interface. That's the only way he could have run that utility. While I can't say for sure, he may well not have erased the drive at all, but if he did, he would have had to do it on a Mac. It can't be done from a Windows system. What exactly he did is impossible for any of us to say.

Again, I think a failing hard drive quite likely, as others in this thread have also indicated would be their suspicion.

Regards.

lifewebb wrote:

I have downloaded and used the DriveDX software. It astonished me by hardly being open for 5 seconds and then delivering its reports. How did it manage that I wonder...

All DriveDx does is use a free open source utility to ask the drive for its health information which consists of very little actual data to transfer.

Perhaps I should run it again in an hour or so.

There is no need unless DriveDx would alert you to a change. Since there are no obvious immediate issues, then the report will be nearly the same.

I have one comment about the DriveDX reports concerning the Temperature measured. It is 17 degrees C right now, before sunrise on the west coast of Mexico. The iMac has a little heat emerging from vents on the back but is otherwise cold to touch. I was perplexed at the high Temp reading of 34 C. I would expect the fan to be operating at that temp but it's not.

The only temperature I'm a bit concerned about is for the Seagate hard drive that reached a Lifetime Max Temperature of 60ºC, but that is probably due to being installed inside of an iMac that runs hotter than most systems. It is still within the manufacturer's safe range, but Seagate drives typically run cooler than most other brands. The 34ºC hard drive temp is actually quite good especially in an iMac.

Yesterday, Jan 17, I finally did a Disk Utility check of the HDD inside Recovery and it came up with a failure on the Data volume. Pictures attached.

This result is leading me to decide to erase and reinstall and see if my problems go away. I was going to do it this morning but have stopped in order to respond to your kind input.

Try running First Aid on the hidden Container. Within Disk Utility click "View" and select "Show All Devices" so that the hidden Container appears on the left pane of Disk Utility. If after several scans the errors remain, then a clean install is the only option to correct them by using a fresh file system.

lifewebb wrote:

2) by attempting to over-write OS Sonoma with Sequoia as System Settings keeps urging me to do.

Upgrading to a new major version of an OS should be avoided until your existing issues are resolved. Upgrading to a new major version of an OS just adds extra unknown complications & compatibility issues.

However, it is Ok to install the minor OS update patches since they could fix some problems and are unlikely to introduce any new compatibility issues.

Yesterday I did all my backing up manually to two external drives and then decided to answer Apple's call to update the OS to Sequoia. I thought this might erase any System level problem at the root of the many crashes and restarts phenomenon.

The macOS system files are now on a read-only signed & sealed system volume which cannot be modified by the user, so those system files are fine.

Signed system volume security - Apple Support

Reinstalling macOS over top of itself these days will only rarely fix a boot related issue....it won't fix other issues.

And upgrading to a new major version of macOS such as going from Sonoma to Sequoia just complicates the whole troubleshooting procedure by introducing all sorts of new compatibility issues.

However, the process aborted about half way through, see image below, + Text Edit crashed, so I could not keep a record of what the detailed reason was for it aborting & System Settings crashed,

My plan is to have a technician erase the drive, without dismantling the iMac and putting the Fusion drive into some external setup. Install OS Sequoia ONLY from Apple's servers, not from some copy sitting on one of his external drives.

Only after this attempted rectification has been done, and has failed to cure my problems, will I move to believing that the only solution is to replace the Fusion Drive with an SSD.

I am fairly confident the internal SSD & Hard Drive are fine for the moment since I don't see anything in the DriveDx reports to cause me any real worries, at least not for anything you've described here.

My focus would be on those third party memory modules. Either one of them is bad, or they are just not compatible with your Mac.

I am at the end of my tether as you can see!

Troubleshooting computers can be a very long & frustrating experience at times even for experienced techs. The more recent Macs make it even more difficult due to all the hardware, software, and security changes. Plus advising people remotely where we cannot see anything makes it even more difficult.

All thanks to everyone else who has chimed in with valuable information and suggestions. So much appreciated having the chance to discuss my situation. :-)

You're welcome.

Good luck with your local tech. Please follow up when the issue is resolved whether it is having this iMac repaired, or purchasing a new one & recycling the old computer.

lifewebb wrote:

I could tell you that I bought two 16GB modules from Amazon MX, thinking that it would make the computer even faster and they were sold under a brand called TimeTec which allegedly were the correct ones for this iMac 2019,1 - 27 inch screen. Compatible with Apple DDR4 2666MHz / 2667MHz for Mid 2020 iMac (20.1 / 20.2) / Mid 2019 iMac (19.1) 27-inch with Retina 5.

I have seen mixed results for people using the TimeTec memory & SSDs.

Plus, memory very rarely increases system performance unless your workloads require it It is very easy to determine if memory is hurting system performance. Use the computer for days without rebooting while doing your tasks making sure to also perform the heaviest workloads.

Then use Activity Monitor to check the memory usage. If the Memory Pressure graph is:

• red, then you need more memory.
• yellow, then you are borderline on having sufficient memory
• green, then check the Swap Used and Compressed Memory...if they are in the GB range, then you probably need more memory (especially if it is more than 2GBs).

The file system issues can easily cause performance issues, plus the Fusion Drive is a bit of a limiting factor. Of course 8GB of original memory is very limiting except for the most basic tasks. I don't know why Apple sells sub-par configurations without a clear warning that such a system is for only very basic usage since most average users won't realize it.

I discovered that the 16GB modules had been made by the same manufacturer that Apple had used for its 4GB modules - SKhynix.

While the memory chips may be the same, that is not the complete story. The supporting electronics on the memory stick must also be of high quality. Typically the minor players will skimp in order to save money so they can sell their products for less to make them more attractive. Plus those Skynix chips may not be 100% quality...they could be chips that did not pass all the rigorous tests other memory manufacturers require.

FYI, lots of manufacturers, even good ones may utilize partially bad chips by bypassing the bad sections in order not to lose money. So lets say a memory chip can support 4GB, but a 1GB portion is bad, they may use the remaining 3GB section. Usually that is not a problem if section used is 100% good.

It was a test of my own devising. Now the RAM consists of two 16GB blades which are correctly installed as the first two modules at the bottom of the tray. However, the day after doing this change, the computer again crashed and its report said 'Possible memory corruption'! So, I am no further on with whether the physical RAM is causing trouble.

The memory should be installed in the 2nd slot from the top and the bottom most slot IIRC. That should be the way the memory was installed from the factory. I've never seen memory in an iMac from the factory installed in slots next to each other.

Run MemTest86 to see if any issues are detected. Unfortunately the free version of the app is limited to just running the test in four loops each time, however, it can still have a good chance at detecting a memory related issue. With 32GB those four loops will likely take a day to complete (perhaps longer).

I would suggest reinstalling the original Apple memory back by themselves without the TimeTec modules to see if MemTest86 detects any problems and to see how the system performs. It is also possible the mix of Apple & TimeTec modules together is the problem....sometimes memory is not compatible with other memory. If you use both at the same time, then I would alternate the slots used by the Apple & TimeTec modules so matching pairs are in the DIMM0 slots and the other matching pair in the DIMM1 slots.

FYI, it can be very difficult to troubleshoot memory related issues unless the failure is extreme or very repeatable.

1) EtreCheckPro is an excellent tool for finding software and hardware problems.

Download and run the free version of EtreCheckPro, from > https://etrecheck.com/en/index.html

Then post your Report, as per > How to use the Add Text Feature When Post… - Apple Community

2) If it is crashing and restarting when you wake it from computer sleep mode.

Then test the following Energy and Lock Screen Settings.

Turn On "Prevent automatic sleeping when display is off"

Set "Turn display off when inactive" to 5 or 10 minutes

Leave the iMac On and only allow the display(s) to turn Off

Do not manually Sleep from the Apple Drop Down menu

Shut Down the iMac when your away for a day or more

It would be pure guesswork of little use one way or the other. FWIW, I’ve used the utility on Windows and it does absolutely no harm other than to query the disk for already saved information and display it in usable format.

What you can do is to reset your Mac to factory and reinstall apps afresh and see if that restores normal operation. Be careful not to involve Time Machine during any part of resetting to factory: manually copy data files like docs and jpegs and PDFs to external disk for restoring later.

Before trying all that, see if you can get lucky with the settings below set exactly as shown (restart after changes).

Additionally, make sure your displays is set to sleep on timer in case you forget to lock your computer between breaks:

lifewebb wrote:

Re. Etrecheck - I am amused to inform you that I did try that and it immediately crashed! Twice. Would not do its work. Nothing I could do! I think I have a report for that one.

Startup in Safe Mode, as per > Start up your Mac in safe mode - Apple Support

Then see if you can run EtreCheckPro.

den.thed wrote:

1) Where did you get those 16GB RAM modules.? They look OK.

Although you might want to swap the modules in Bank 1 and Bank 2,

so that the 16GB modules are on DIMM 0 and the 4GB modules are on DIMM 1.

https://discussions.apple.com/content/attachment/c5343b01-a307-4242-a9b9-dba96fd843e3

I was thinking the same thing, but I recall several years ago where installing the memory in the configuration the OP has actually gained extra performance....plus a high level forum contributor had mentioned it was the correct configuration when I pointed out pairs should be in DIMM0 slots, then in DIMM1 slots. However, you are correct that matched memory module pairs should usually be installed first in the DIMM0 slots and with extra memory into the DIMM1 slots.

Unfortunately I am not aware of any official documentation. Here is the Apple support article for installing memory into an iMac. The relevant section is Step #9 (the first Step #9 where the memory is accessed by the back panel) where it mentions you are correct in how the memory slots should be populated (the documentation is a bit confusing as is usual for Apple these days):

Install memory in an iMac - Apple Support

iMac (Retina 5K, 27-inch, 2020) DIMMs have a notch on the bottom, slightly left of the middle. If your DIMMs are mixed in capacity, minimize the capacity difference between Channel A (slots 1 and 2) and Channel B (slots 3 and 4) when possible.

I would also wonder about the third party memory upgrade since Macs are very picky about the memory they use. There is more to memory compatibility than the main memory speed since there are lots of other critical timings that Apple does not document so there is usually no way to confirm compatibility unless the memory vendor guarantees compatibility for the exact parts purchased. Crucial & OWC do this when using the tools on their respective websites to identify compatible memory for a specific model computer.

No, a disk controller is the disk's own built-in embedded chip that communicates with the computer. It translates the generic peripheral bus commands the computer uses into disk-specific control and electrical signals to actually operate the disk itself.