Oh dear, another iMac freeze.......

[Geoff777]

I mentioned in another thread that when I fist downloaded Big Sur, the desktop basically froze and the only remedy was to power off at the switch and power on again. That was 2 or 3 weeks ago and it's been running fine ever since..... until today.

I was scrolling through email in Outlook and it just froze. Nothing clicked reacted. Did a force quite which came up with the open apps and Outlook was highlighted. Couldn't click it so hit return and Outlook shut down.
The other open apps wouldn't respond, and I couldn't click to choose another app in force quit.

Funnily enough, the dock did magnify, but none of the apps would open when clicked.

So, shut down with the power button, again. Switched on again and so far so good, bit no usual warning of "shutdown because of a problem.... send report to Apple".

Other apps open were Preview, Word, Safari and Telegram.
iMac is a 2017 27" with 24Gb ram.

Anyone else having similar problems on iMac (I see a thread of similar issues on M1 MacBooks)?

 

[Geoff777]

Aaaaaand..... it just happened again! Scrolling again but this time on Safari. Funnily enough looking at Huawei tablets...

Is this happening to anyone else or is my iMac hardware playing up? It's only 3 years old but it did suffer separation of the fusion drive when I loaded Catalina.

Any advice welcomed!

 

[SketchyClown]

What size was your Fusion Drive? At some point after 2015, Apple started getting chintzy with the SSD portions of some of the smaller Fusion Drives. I believe they chopped them down to 32GB or 24GB in size from 128GB. If Catalina broke your Fusion Drive, I would check how much free space is available on the SSD portion. Because if that's where the OS is installed, it wouldn't take much to fill it up. Then if the system wants to page to Virtual Memory, that could be causing freezes.

Also, I believe you can still use a Fusion Drive with Big Sur.

If you ever want to fix it, and don't mind reinstalling Big Sur, you can go into the Terminal in either Recovery mode or from a USB installer and issue the command "diskutil resetFusion" and it will recreate your Fusion Drive.

 

[Geoff777]

What size was your Fusion Drive? At some point after 2015, Apple started getting chintzy with the SSD portions of some of the smaller Fusion Drives. I believe they chopped them down to 32GB or 24GB in size from 128GB. If Catalina broke your Fusion Drive, I would check how much free space is available on the SSD portion. Because if that's where the OS is installed, it wouldn't take much to fill it up. Then if the system wants to page to Virtual Memory, that could be causing freezes.

Also, I believe you can still use a Fusion Drive with Big Sur.

If you ever want to fix it, and don't mind reinstalling Big Sur, you can go into the Terminal in either Recovery mode or from a USB installer and issue the command "diskutil resetFusion" and it will recreate your Fusion Drive.

Hi Sketchy
Thanks for replying! Tried using Disc Utility but couldn't make any sense of it so found out by typing diskutil list into Terminal and appears to me that the SSD bit is 121gb..... does that sound right????
No idea how much is free.... 🥺

If it carries on I'll try your tip, many thanks!

 

[SketchyClown]

Yes, that looks right, the 2TB/3TB Fusion Drives came with the larger SSD portion.

Just looking at your screenshot, it looks like both disks are under an APFS container scheme to disk2 which looks like a 2.1TB Fusion Drive. Try typing "diskutil APFS list" in the Terminal and see if it shows them set up as a Fusion Drive. It is possible that the machine itself reset the Fusion up at some point.

So if it is set up as a Fusion Drive then you may be experiencing the same thing that happened to me with my iMac, and that is that the old Seagate 2TB rotator HDD is dying. These are the worst HDD's ever IMHO. This caused random system freezes for me with no known cause. The remedy at that point to make the machine usable was to de-fuse the drives, restore macOS onto the SSD portion, and replace the Seagate.

Might wanna download DriveDX or something similar to check the HDD for bad sectors.

 

[Geoff777]

Yes, that looks right, the 2TB/3TB Fusion Drives came with the larger SSD portion.

Just looking at your screenshot, it looks like both disks are under an APFS container scheme to disk2 which looks like a 2.1TB Fusion Drive. Try typing "diskutil APFS list" in the Terminal and see if it shows them set up as a Fusion Drive. It is possible that the machine itself reset the Fusion up at some point.

So if it is set up as a Fusion Drive then you may be experiencing the same thing that happened to me with my iMac, and that is that the old Seagate 2TB rotator HDD is dying. These are the worst HDD's ever IMHO. This caused random system freezes for me with no known cause. The remedy at that point to make the machine usable was to de-fuse the drives, restore macOS onto the SSD portion, and replace the Seagate.

Might wanna download DriveDX or something similar to check the HDD for bad sectors.

Thanks very much for your help. I typed in that command at near the top got "APFS Container Reference: disk2 (Fusion)" So, I guess it is working as a fusion drive??

I checked the HD make and it's Apple (Seagate family) 🥺

I downloaded the trial version of DriveDX and am very impressed.... I'll be buying it! $19.99 could save me a whole lot of heartache later on! Everything is green, there are no error logs and a short self test found no errors so my fingers are crossed for now!

Thanks again for all your help and advice.👍

 

[SketchyClown]

Yes, you have a Fusion Drive.

DriveDX is a good tool, however the system extension has not yet been updated so that it will read external drive SMART status, so you may wanna hold off until it's updated for Big Sur.

I would keep an eye on the disk for sure, those Seagate have possibly the highest rated failure rate of all HDD's.

Good luck.

 

[Geoff777]

Thanks again, I will probably wait for the DriveDX update before buying.
I will definitely keep a close eye on the hard drive..... disappointed it's a not very reliable Seagate..... and will make sure I back everything up!

 

[SaSaSushi]

Yes, you have a Fusion Drive.

DriveDX is a good tool, however the system extension has not yet been updated so that it will read external drive SMART status, so you may wanna hold off until it's updated for Big Sur.

I would keep an eye on the disk for sure, those Seagate have possibly the highest rated failure rate of all HDD's.

Good luck.

DriveDX has been working perfectly for me in Big Sur with my external USB drives so the current extension does work.

However, after restarting my iMac now (unlike in Catalina) I do have to turn the external drives off, unplug and plug in again then power them on in order to get them to appear in DriveDX.

Once, I do so they continue to be displayed properly with full SMART data even when mounted/unmounted.

 

[gilby101]

However, after restarting my iMac now (unlike in Catalina) I do have to turn the external drives off, unplug and plug in again then power them on in order to get them to appear in DriveDX.

That is how it works for me - restart with disk unplugged. For me that is NOT working perfectly. Good enough for diagnosing problems, but not for ongoing monitory of disks.

The required kext is no longer being maintained and DriveDX do not seem have the will (or maybe it is capacity) to update it to BS's requirements. And who knows when Apple will block the kext? I don't see a quick resolution of this issue.

The only resolution I can see is for Apple to support SMART queries to external drives.

 

[SaSaSushi]

That is how it works for me - restart with disk unplugged. For me that is NOT working perfectly. Good enough for diagnosing problems, but not for ongoing monitory of disks.

I'm sorry to hear that.

Perhaps its a drive-specific issue in BS with the old extension? Two my external HDD are in a noisy USB 3.1 Gen.2 RAID 1 enclosure that I keep unmounted at all times except for when CCC runs a daily backup to it for 20-30 minutes a day and DriveDX continues to report occasional changes in SMART status.

The only resolution I can see is for Apple to support SMART queries to external drives.

Yes, this would definitely be nice.

 

[SketchyClown]

YAY! I installed the v1.10 of the SAT SMART Driver, rebooted with drives unplugged, then plugged them in and launched DriveDX and all drives are reporting.

I'm sure that they will find some way to get the new BS extension framework to work for this eventually, but since I do not reboot my machine often, this will work fine for now.

 

[gilby101]

I installed the v1.10 of the SAT SMART Driver,

Where do I find that version? I am only aware of versions 0.8.2 and 0.10.2 as described on DriveDX web site.

 

[SaSaSushi]

Where do I find that version? I am only aware of versions 0.8.2 and 0.10.2 as described on DriveDX web site.

I'm guessing SketchyClown meant 0.10.2 since that is the most recently updated version I'm aware of.

0.10.2 is what I'm running.

 

[SketchyClown]

I'm guessing SketchyClown meant 0.10.2 since that is the most recently updated version I'm aware of.

0.10.2 is what I'm running.

Yes, that would be correct.