Despite its benefits take up of IPv6 has been slow, and many sysadmins disable it by default. That's a bad idea, since there is no easy way to change the setting back automatically across multiple machines.
IPv6 picture from Shutterstock
Microsoft experts Ray Zabilla and Mark Morowczyski point this out in a post discussing the importance of IPv6:
If you need to re-check that box there is NO PROGRAMATIC WAY to do so. So if you have gone ahead and built that uncheck in your image and you do need IPv6 on that network adapter you’ll need to log into EVERY MACHINE AND RE-CHECK IT. Oh how fun that will be.
Better to leave it enabled, then. Hit the full post for more discussion of IPv6 issues.
Why you need to care about IPv6 [Microsoft Ask PFE Blog]