Nexus 6 unable to mount e drive - marshmallow

Hi all,

I updated my N6 to Marshmallow last week and rooted using the NRT and when I try to change the kernel it gives me the following error in recovery:
Finding update package...
I:Update location: /sdcard/ElementalX/ElementalX-N6-3.04-express.zip
Opening update package...
E:unknown volume for path [/sdcard/ElementalX/ElementalX-N6-3.04.zip]
sysutil: Unable to open '/sdcard/ElementalX/ElementalX-N6-3.04-express.zip':No such file or directory
E:Failed to map file
Installation aborted.

I am unable to mount sd card from recovery, can anyone help resolve this issue/point me in the right direction?