I've run that command successfully on both HDDs and SSDs, so I guess something about your fusion drive is stymying it.

I'd try again after changing "rdisk1" to "disk1," and if that's still a no-go, we may need some input from V1 (who originally posted the command).


The new Great Equalizer is the SEND button.

In Memory of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire