Fusion drive issues after installing Catalina 10.15.5 supplemental update

[magill515]

My 2017 iMac (Retina 5K, 27-inch, 2017) has been very stable since I got it new in 2017. I've been very prompt about updating the os High Sierra --> Mojave --> Catalina and have never had any issues.

I use Acronis True Image 2020 daily for full system backup and recently this backup started failing with 'a backup error' - not much to go on there. It seems to me that that this started immediately after the 10.15.5 supplemental update a few weeks ago, but I cannot be absolutely sure it's related. Specific folder backups (not full) are fine from the same fusion drive and I get the same error doing a full system backup to a different external drive. It seemed to point to the MacIntosh HD fusion internal drive. I am not experiencing any other app issues with the drive.

First Aid on both parts of drive show as fine.

I installed DriveDx and it is showing errors on the sata portion of the fusion drive: (see attached output)

Reported Uncorrectable Errors 5734
Current pending sector count 8
Offline Uncorrectable Sector Count 8

Is my fusion hard drive failing? Is anyone else experiencing this?

Time machine backups seem fine.

I'd appreciate any comments.

 

[SketchyClown]

I also use DriveDX, it's been kind of a staple for a few years now. I have had 2 iMac's with a Fusion Drive, a Late 2013 with a 3TB and my current Late 2015 with a 2TB. Both of my factory Fusion Drive's have failed. With the screenshot provided, I would vote that the HDD portion of your Fusion is failing. My personal opinion is that the cheap Seagate drives are always the culprit, and they fail out of nowhere. DriveDX is good at sniffing this out. If you're still under a 3yr Apple Extended Warranty, I would get it in and get them to replace it on their dime.