Make sure Thunderbird is set up as the default email client on the desktop. * https://support.mozilla.org/en-US/kb/make-thunderbird-default-mail-client * https://community.windows.com/en-us/stories/setting-default-apps re :''They do come into desktop Outlook (which I don't want) ''. Stop Outlook from running. It might be set up as the default email client and also set up to auto start up minimised when you start up computer and set up to be running in the background. The link below has information which sounds like this is what is going on. * https://answers.microsoft.com/en-us/msoffice/forum/all/outlook-running-in-the-background/d7889e82-151f-4a0e-a06e-5d7aae15e1f8 How to change which apps auto run on startup: * https://support.microsoft.com/en-us/help/4026268/windows-10-change-startup-apps But if you really do not want Outlook to access emails even if you do start it up, then remove the account from Outlook.