Due to an error in the disk manager, a yellow colored exclamation mark is shown in Microsoft ISATAP and 6to4 adaptor resulting in the loss of internet connection. The ISATAP device enables companies to gradually shift to an IPv6 infrastructure by encapsulating IPv6 packets using headers. Thus, the traffic is carried over by the IPv6 infrastructure without the company spending resources and money for the conversion. To solve this issue, the 6to4 adaptor must be uninstalled from the Device manager. Then it is required to add Microsoft 6to4 adaptor as the new network adaptor by manually selecting it from the list. After installing the new hardware, the PC must be restarted.

Issues

A yellow exclamation mark is found at the Microsoft ISATAP 6to4 adaptor.

Sometimes we lose the internet connection because of an error in the Device Manager and a yellow exclamation point is found on "Microsoft ISATAP " and on "6to4 adaptor".

According to Microsoft support, we can ignore this problem, the card will work properly. But the problem is that in most cases, we lose our internet connection.

Microsoft ISATAP

According to the Microsoft site:

A Microsoft ISATAP device (inter automatic tunneling protocol address of the site) is used to help companies transition to an IPv6 infrastructure. ISATAP encapsulates IPv6 packets using IPv4 header. This feature allows the customer to carry IPv6 traffic over an IPv4 infrastructure. This approach enables organizations to slowly migrate to an IPv6 infrastructure without having to spend much time and financial resources to convert to the new infrastructure.

Solution

Open Device Manager (Start / Run or Windows Key + R, enter: devmgmsc).

Right-click on Adapter 6to4.

Choose "Uninstall".

Then in the top menu, select "Action" / "add hardware, then "next".

Select "manually select from a list" /"network adapter (or network cards)" /"Microsoft"/"Microsoft 6to4 Adaptor".

Finally, select "finish installing new hardware".

Restart the PC.

Normally, there should be no more problems in the device manager and the network connection should be back.