problem of denied access using kvm

I would like to test kvm with opensuse tumbleweed. I successfully installed kvm, but I am stuck in creating my first VM. The trick is that I want to have the VM's directory in an external HDD. When I set the directory of the VM file I get this error message: > Impossible de terminer l'installation : « Cannot access storage file > '/run/media/lowley/424b7b47-883d-42ac-b6f3-994c0c01c01f/sauvegardes/fedora-haskell.qcow2' > (as uid:471, gid:10): Permission denied » I am not very strong in managing user rights. I set root belong to the kvm group, but I still have this error. can you help me? thank you olivier EDIT I launch it by a entering virt-manager, as me and not as root. In fact I have a shortcut on the desktop.