I encountered this problem with my non privileged user accounts using Windows 10. When Genymotion runs for the first time as the current user, it will create a virtual interface if it does not see one defined in the users profile. If your account has Administrator privileges, it will create the interface without issue. As a non privileged user, you will get prompted for admin credentials so that a new virtual interface can be created and defined.
My workaround was to run Genymotion with an account that has administrator privileges so that the virtual interface is defined and the Genymotion interface starts up. After that, I preserve the following directories in:
C:\Users\%USERNAME%.VirtualBox and
C:\Users\%USERNAME%\AppData\Local\VirtualStore
When I have a new user that needs to run Genymotion, I have them run a script that restores these directories to their profile. They can then run Genymotion without needing Admin credentials.