Comment 7 for bug 1613264

I had this problem too. Basically, I followed the guide on https://help.ubuntu.com/community/KVM/VirtManager and ran the command `sudo apt-get install virt-manager ssh-askpass-gnome --no-install-recommends`. I think OP followed the same guide and therefore bumped into this issue. This is therefore not a bug as this package is not essential for this application to run but rather a very useful add-on. With a quick google you immediately find out what to do if you want this functionality. The wiki page might need an update.