Observed a null pointer exception due to polling for ziflist changes whilst adding/removing devices. According to MSDN GetAdapterAddresses may need to be called multiple times in cases where a device has been added/removed.

Note that it is possible for the buffer size required for the IP_ADAPTER_ADDRESSES structures pointed to by the AdapterAddresses parameter to change between subsequent calls to the GetAdaptersAddresses function if an adapter address is added or removed.

From: https://msdn.microsoft.com/en-us/library/windows/desktop/aa365915(v=vs.85).aspx