This happened to a colleague of mine who has decided to upgrade his pc with windows 8.1 to windows 10. At the end of the update process, completed without errors, the operating system was not able to see the network devices correctly (both wifi and ethernet) leaving the pc without connectivity.
Checking in device manager the network adapters were present, and all seemed ok, While going to check network connections there no connections were present:
The solution is to delete this registry key via regedit (I recommend not to delete it from command line otherwise it will not work, it is not cancelled):
and then launch this command:
netcfg -v are dni_dne
This is the reference microsoft KB, it talks about wireless networks but actually it applies to any type of connectivity: https://support.microsoft.com/it-it/kb/3084164
I forgot to say that the problem seems to be related to the fact that there is installed one or more vpn clients that are not supported during the upgrade, in this case, probably the cisco vpn client and the sonicwall global vpn client.