Re-install worked as expected Fresh install after I deleted 'Thunderbird' folder in Appdata. That is what I missed and must have the profile The new install went as expected and then Kaspersky Internet Security popped up a warning about the server. I clicked 'Finish' and Thunderbird downloaded emails and asked for default choice. Confirmed default client and tried a test message to my mobile. Thunderbird asked for password again. Should I tick the "Use Password Manager" for the passwords? I assume Thunderbird is referring to it's own manager and not my LastPass manager? I gave Thunderbird the password and error dialogues popped up. Closed the dialogues and quickly tried the test mail again. Thunderbird appeared to stall in the "sending" process. Cancelled out and discarded changes, shut down and set up second test mail, told Kaspersky to 'Continue', had a couple of arguments with Kaspersky and it shut down. 'Send' email worked immediately and more tests to other mail addresses working now. To me it does not look like Thunderbird is a problem here Your opinion would be most appreciated Thanks Greg