Also I have a back-up of Mojave. I am trying to boot up from that back-up but I get...SDErrorDomain error 104
I need to retrieve some info from Mojave. Any ideas?
The most recent result that a quick Google search turned up is: "It indicates the selected disk cannot be used as a startup disk to boot up your Mac, and the reasons behind this error could be: Startup settings prevent booting from external disks. The drive format is incompatible with the installer."
It may be related to a setting you need to change while in Recovery mode.
To the point, though, why can't you retrieve your data by accessing your Mojave installation via Finder...without booting into Mojave?