Hi Wayne,

Teredo tunneling is a transition technology that gives full IPv6 connectivity for IPv6-capable hosts which are on the IPv4 Internet but which have no direct native connection to an IPv6 network.

Please ensure that the adapter is completely uninstalled from the computer before installing it again as you might have only deleted some files but not the complete setup.
To uninstall Microsoft Teredo Tunneling Adapter follow the below steps:

1. Click Start. In the Start Search box type "devmgmt.msc" and press Enter.
2. Expand "Network Adapters", double-click on the entry of the network device.
3. Click the tab "Driver", click "Uninstall".
4. Click Start. In the Start Search box type "appwiz.cpl" and press Enter.
5. Remove the entries related to the network adapter.

To install Microsoft Teredo Tunneling Adapter again, follow the below steps:

1. To install it go to device manager OR Hold the Windows Key and Press R. In the run dialog that opens, type hdwwiz.cpl and Click OK.



2. Once in the Device Manager -> Click Network Adapters


3. Then click the Actions tab from the top and select “Add Legacy Hardware”




4. Click Next and Next again and Next again (it will not find anything, so do not worry). You will then be taken to Common Hardware types, select.

5. Scroll down and select Network Adapters then Click Next. You will now be taken to the Add Hardware dialog.

6. Now from the Manufacturer tab select Microsoft then from the Network Adapter tab select Microsoft Teredo Tunneling Adapter and Click Next.



7. After you click Next, Click Next again then Click Finish.

8. Now the issue should be resolved.

However If you still see a yellow exclamation mark then try the below steps to resolve it as well:

1. Open Registry Editor by clicking the start button and type regedit and press Enter. 
2. .Navigate through the following: HKEY_LOCAL_MACHINE\SYSTEM\CURRENTCONTROLSET\SERVICES\TCPIP6\PARAMETERS. 
3. In the right pane, right click Disabled Components and select Edit. Set the DWord value to 0.
4. Restart your computer and the Teredo tunneling adapter will now start.

If you still face any issue, please let me know and I will try to provide further assistance.

Regards,
Lokesh