If you want to check if IPv6 is in use in  Windows 10 uses network adapters, do the following:

  1. Click the Windows logo, click on Search and type then open Control Panel.
  2. Click on Network & Internet.(if you do not see this, check that view by (near top right) is set to Category
  3. Click on Network and Sharing Centre.
  4. Click the Change adapter settings item.

  5. You may have multiple listed, if you are on wireless you are looking for an adapter that has the name of the wireless network you are connected to.  If you are connected using a LAN cable, it shoud be one which does not have the Red X on.

  6. Right Click and select Properties

  7. Can you see a check box next to Internet Protocol Version 6 (TCP/IPv6)

  8. If it is checked and you have been asked to uncheck, please uncheck that one and click on O