Help/Troubleshooting Info, Profile Folder, Open Folder, close TB, open the account subfolder, e.g. ImapMail/imap.comcast.net, delete Inbox.msf and Inbox, restart TB, and the Inbox contents on the mail server will automatically download and create new Inbox.msf and Inbox files.

The xfinity email still pops up and I am still told 'tbird failed to connect', and no emails can be downloaded.

re :I have removed all xfinity emails on the original email server

That would mean you have nothing on the server. Do you have a Pop or Imap account in Thunderbird ?

re :An email from xfinity that includes a link to my xfinity account attaches itself to my tbird program in such a way that no new emails can be received....The xfinity email still pops up....Nothing removes the problem message.

What email are you talking about? Why would xfinity send you an email ? Is it a scam email trying to force you to use the bogus link ?

You have not stated what folder has that potentially scam email, so I'm assuming it is either in the Inbox or in Junk/Spam.

Do this:

1. Delete the xfinity email from whatever folder it's in.
2. Empty Junk
3. Empty Trash
4. Right click on 'Inbox' and select 'Compact'
5. Right click on 'Junk/Spam' and select 'Compact'

REstart Thunderbird.

Note if you have removed all emails off the server via webmail account then there will be nothing to download. If you use an imap account then you may discover you have lost all emails as they can only display whatever is on server.

Logon to webmail account and check it has been enabled. https://login.xfinity.com/login

In xfinity webmail account have you set it up to allow downloading to third party email clients ? https://www.xfinity.com/support/articles/third-party-email-access

Image below as a guide

If this check box is not selcted then access is being blocked. Confirm it has been selected.

See this topic for Xfinity server settings:

https://support.mozilla.org/en-US/questions/1504463#answer-1725517

This has happened before and was only solved by deleting every possible thunderbird element from my laptop, (including my calendar, which later took many hours to re - update). An email from xfinity that includes a link to my xfinity account attaches itself to my tbird program in such a way that no new emails can be received. I have cleaned the cache, opened task manager and closed every tbird open link, I have removed all xfinity emails on the original email server (also xfinity). Nothing removes the problem message. Is there a way to remove it without removing the whole tbird program (and then reinstalling)? It was such a pain to do this last time around. When you do a normal clean out it doesn't actually remove every element. Going in to find every little thing causes me a lot of effort and stress. This one faulty message is making me give up on tbird altogether. Thanks for your help! Annie

Ugh, that sounds super frustrating. Have you tried starting Thunderbird in Safe Mode (Help > Troubleshoot Mode) and see if the bad message still blocks things? Also maybe check the profile folder and delete the specific inbox file (like `Inbox` and `Inbox.msf`) for that account just back them up first. Might clear the stuck message without nuking the whole setup.