Important Internet Protocol version 6 (IPv6) is a mandatory part of Windows Vista and later versions of Windows. We do not recommend that you disable IPv6 or its components. If you do, some Windows components may not function. Additionally, system startup will be delayed for 5 seconds if IPv6 is disabled by incorrectly, setting the DisabledComponents registry setting to a value of 0xfffffff. The correct value should be 0xff. For more information, see the «What are Microsoft’s recommendations about disabling IPv6?» question in IPv6 for Microsoft Windows: Frequently Asked Questions.