Some builds of Windows 10 has broken OpenVPN TAP Adapter

 No rebooting required:

1. add string value/data ComponentId/tap0901 (REG_SZ) with regedit value name=ComponentIdvalue data=tap0901
   to key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e972-e325-11ce-bfc1-08002be10318}\[0001]
   where [0001] stands for the instance on your system in which you find the REG_SZ string with
   value name=ProductName
   value data=TAP-Windows Adapter V9
2. disable and enable TAP-Windows Adapter V9 in device manager>network adapters to reinitialize the driver with the newly added ComponentId

Users with Kaspersky Internet Security install might still have issues after following this tutorial. 

In order to resolve - You will need to remove Kaspersky, reinstall the VPN / Tap drivers then install Kaspersky back.

1) completely removed the Kaspersky (2015/2016) with program http://media.kaspersky.com/utilities/ConsumerUtilities/kavremvr.exe ;

2) Install the latest version of VPN application and or OpenVPN / Tun-TAP drives NDIS (6)

3) Install Kaspersky (http://www.kaspersky.com/product-updates);