(error code 112)Mount of BaseSystem failed

wess-Mac:~ wes$ sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

Password:

Ready to start.

To continue we need to erase the volume at /Volumes/MyVolume.

If you wish to continue type (Y) then press return: y

Erasing Disk: 0%... 10%... 20%... 30%...100%...

Copying installer files to disk...

Copy complete.

Making disk bootable...

Couldn't mount dmg /Volumes/Install macOS High Sierra/Install macOS High Sierra.app/Contents/SharedSupport/BaseSystem.dmg (error code 112)Mount of BaseSystem failed.

Done