internal error: could not get interface XML description: File operation failed – Failed to read (null)

Installed virt-manager on my ubuntu server, and when trying to use it, kept getting this error:

internal error: could not get interface XML description: File operation failed - Failed to read (null)

The culprit was the virtual ethernet interface that I had created on the host (eth0:0)

Here is more info on the bug:
https://bugzilla.redhat.com/show_bug.cgi?id=1185850

removing the virtual network interface solved the issue.