error grub-install: error: failed to get canonical path of `unionfs'

ibouvousaime

the goal is to repair a windows install, Im running puppy linux trusty thar 6.0 live USB atm and Id like to install grub2 on my hard drive so I can boot the windows 7 iso either from the iso or from a partition where its contents have been extracted to, with puppy Im unable to extract the iso so far and mounting the iso fails, Ive managed to install grub2 on the live iso but when I try to install it on the pc I get the error " error grub-install: error: failed to get canonical path of `unionfs' ", how can I get past that error, and how can I make grub2 boot from my windows iso file afterwards ? I hope I gave enough information to solve this. Thanks in advance