Originally Posted By: ryck
Originally Posted By: joemikeb
NOTE: Beginning with High Sierra (MacOS 10.13) Apple does NOT permit a surface scan of the boot drive.

Well, that's a pain....I'm 10.13.6. I suppose that's the reason I get "dd: /dev/rdisk1: Operation not permitted". I wonder what the logic is behind a surface scan prohibition.

On the downside I suppose I just have to wait and see if the world comes to an end but, on the upside, I save a hundred bucks by not having to buy TechTool 11.

I've already posted that the command runs on my boot SSD from my Mojave 10.14.5 boot volume, so joemike's statement is inaccurate on at least some level.

I think - just for the heck of it - you ought to try booting from your external and seeing if the command runs.

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