Catalina Kernel Panics from Fusion Drive's dead HDD


macrumors 65816
Original poster
Jun 10, 2009
I decided to upgrade to Catalina 10.15.2 from Mojave. It caused constant kernal panics whether during install, using it normally or even shutting down.

Thinking it was a 10.15.2 problem I upgraded it to 10.15.3.

It still caused kernel panics even doing a clean install directly to 10.15.3

So I ended up clean installing Mojave 10.14.6 + security patches for January 2020.

No more kernel panics.

Posting this here in case anyone with a 2012 iMac 27" ever encounters this problem.

Now looking forward to installing a 4TB Samsung 860 EVO SSD into this iMac. Hopefully it will extend the useful life to for another 3-7 years or until the iMac 32" comes out.
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