dreadlock

I'll have another go and get back. Urrm, must be me. It seems to have worked now. Thanks sierratango

That's strange. I've done it on both of my PCs and it stays disabled after rebooting. In fact it doesn't even appear in Device Manager anymore. Make sure when you input that line into Command Prompt, you receive an "Ok." output. I'll have another go and get back.

Thanks for pointing that out. If you enter "netsh interface teredo set state disabled" into Command Prompt (Admin) it appears to permanently disable the adapter even after a reboot. Thanks sierratango but I tried that too and the Teredo still is enabled again after reboot?

THIS fixed the issue. Tried with TS2015 & TS2016 on Win8.1. Had the same problem. Its definetly a Firewall related problem with the Bitdefender Firewall This works for me, however, each time I reboot the Teredo Tunneling adapter is enabled again so I have to manually disable each time. Any suggestions anyone?