I am running macOS sierra on a mid 2012 MacBook Pro, and just recently came across a problem where I can no longer bypass login and got stuck on a loading screen before it eventually goes to a black screen and can no longer get into my Mac.
So, I decided to try and back up my stuff and migrate them to a new Mac I'm buying. I pop the WD Passport drive into the USB, go to the recovery mode and attempted to create a disk image backup from my MacIntosh HD onto it. But half-away, I am met with:
The operation couldn't be completed. (com.apple.diskutility error 3) Preparing imaging engine... Reading whole disk (apple_HFS : 0)... Operation failed with status 5
I haven't got Time Machine activated, and I cannot even get into my Mac to use it. So I am left at a loss, trying to figure out how to create a backup.