USB 3.0 disk not mounting in single user mode I have a MacBook Pro Retina (Early 2013) with MacOS X 10.11. To cut a long story short, due to issues with the NVIDIA card and graphics switching, I'm able to boot into single-user mode, but can't complete the boot past that into the Finder, so I would like to make a back-up of the data while in single user mode before taking the laptop to the Apple Store (since the graphics card issue is a known issue).

However, when in single-user mode, if I plug in a USB 3.0 disk, I get an error after about a second or so, once the disk has spun up:

AppleUSB30XHCIPort:: resetAndCreateDevice: failed to create device after (1) tries, disabling port


and no new device appears in /dev. In contrast, if I plug in a USB 2.0 key, it appears in /dev.

I'm assuming this is therefore a USB 3.0 issue - is there any way to get this to work correctly in single user mode?
Have you tried Safe Booting it? (Will bypass loading discreet graphics kext so you might be able to use GUI)
https://support.apple.com/en-au/HT201262

If you have another Mac with Thunderbolt handy you could put this one into Target Disk Mode and transfer your data through a Thunderbolt Cable?
https://support.apple.com/kb/ph10725

Otherwise it's likely the needed kext for USB3 isn't loaded in single user mode and you're out of luck and need a USB2 storage device.

As a side note the part needing to be replaced to resolve the graphics issue is the main logic board, separate from the storage, so I'm sure if you ask nicely to the Genius at the Apple Store to please not erase your data they won't.

See https://www.ifixit.com/Teardown/MacBook+Pro+15-Inch+Retina+Display+Late+2013+Teardown/18696 showing that it's a separate part.