The DNS server is now booting from the registry or directory. The existing server boot file will no longer be read by the ...

The DNS server is now booting from the registry or directory. The existing server boot file will no longer be read by the DNS server at startup. For any new zones that you add or for changes you make to zone information, you must make them using the DNS console. 
The previous DNS server boot file has been moved to the %SystemRoot%\System32\Dns\backup directory. 
To return to using a boot file, use the DNS console and reconfigure the boot method for the server.  For more information, see "To change the boot method used by the DNS server" in the online Help.