Problem with twrp not being able to specify target storage

Hello :) ! i really really want to make a NANDROID backup to be able to install Xposed without running to any risks, i've tried CWM but it still doesn't support my device (SM-N7505, note 3 neo) i tried TWRP but when trying to make the backup the app is unable to "specify target storage" is there a way i can fix this or an alternate way to make a nandroid backup?

Thanks in advance :)

from xda-developers http://ift.tt/28RO4hp
via IFTTT