Avast wanted to upgrade my programs and one of those was Mozilla Thunderbird. I allowed it to upgrade but then my Thunderbird profile went missing, I managed to re-link this. But now when I get a link in an e-mail Thunderbird comes up with an error message. I tried to link my Avast browser to Thunderbird as it used to be but it no longer works. I have tried everything I can find on the Thunderbird forums but no luck. I wish I had not used Avast to upgrade Thunderbird. Does anyone have any suggestions please?