I understand the concept behind IPv6, but as far as I'm aware, for the majority of users it's of no practical importance. I'm wondering if there's something I'm not aware of. Is there any particular reason why IPv6 is enabled by default in Windows 7 (and Vista)? Are there any important Windows 7 services that rely on it? Any negative consequences to disabling it? Thanks.

In Windows 7 the Home Group feature and Direct Access feature rely on IPv6. Going forward IPv6 will also become important if you are connecting to an Exchange server.Disabling IPv6 rarely fixes anything. It does not normally cause any problems or slowdowns in and of itself. Note that unchecking it in the NIC properties does not disable it and can cause problems. To properly disable IPv6 see the following:http://support.microsoft.com/kb/929852Kerry Brown MS-MVP - Windows Desktop Experience

Thanks for the info. By the way, I can confirm that just unchecking the ipv6 option in the adaptor settings DOES cause some major problems...