SMART reporting on SSD drives in Catalina

Last week I upgraded my iMac to Catalina, and immediately received a SMART failure alert from TechTool Protection, saying that the SSD component of the iMac’s Fusion drive was failing.

Before this, I’m pretty sure that the SSD drives were not being reported at all, i.e. they were not supported. But, I don’t recall seeing anywhere that Catalina included a change to now support SSD drives.

My suspicion was that it was a false report. Maybe a software incompatibility: my iMac is from 2017, and TechTool Pro is also an obsolete version (11.0.5).

And then, after I re-cloned to an SSD external drive and encrypted it, it too was reported as failing SMART! I find it hard to believe that both drives suddenly are simultaneously are failing.

What I’m wondering is, is it macOS that is now returning the SMART data from the SSDs? That is, did something change Catalina? If it isn’t macOS, then is there a way to find the driver responsible?

I did have a SoftRAID beta installed at one point but I removed it long ago, hopefully completely.

Right now Disk Utility says the external SSD’s SMART status is Verified, and the Fusion drive is failing, but Disk Utility doesn’t separate the Fusion HDD from the SDD. Disk Warrior’s smart reporting says that only the HDD is supported and is fine.