Just encountered this setting up a VM. Pressing the Yes button to automatically fix the problem sets extended ACLs on the file. You can see this by running an ls -l on your directory, and checking the permissions for other.
Instead of opening up permissions for all users in other, you can explicitly set them using
From the man page:
Granting an additional user read access
setfacl -m u:lisa:r file
Since I wanted to grant the
libvirt-qemu user execute rights to install my vm, I ran:
setfacl -m u:libvirt-qemu:x
This sets permissions for specific users, without changing the execute bit for an entire group of the directory. I'm a fan of the tighter control. The permissions on the file should read something like
-rw-rw-r-+, with the
+ meaning there are extended permissions set.
You could just press the Yes button and not worry about what it's doing, but I chose to check it out. I was then able to continue setup in virt-manager without running with
sudo and without further error.