I transferred to a new Apple Mac Book Pro in Nov 2025. Downloaded and Installed thunderbird version 144.0.01. No problems. Did updates and started to encounter issue with sending mail. Last updated version was 147.0. Had to go back to version 144 to get a properly working Thunderbird. Is there a bug with version 147 for Apple Mac Sequoia that means you cannot send more than one email at a time from pop3 accounts? I send an email, and then have to quit Thunderbird and re-open if I want to send another email. I have done a lot of testing and checking over the last few weeks to try and get Thunderbird to work properly, but nothing worked. Plus a date edit bug / feature for tasks? I have several accounts, all pop3 apart from 1 Gmail account. No matter which account I start from, if I want to send subsequent emails from a pop3 account, I have to quite Thunderbird. No matter how long I wait to send the email. I tried saving the email as draft, and send later. Does not work. I did not make a note, but I think in my testing I may have been able to send more than one GMAIL email - it is IMAP. I know I did send 1 email from my gmail account, and then tried one of the pop3, but was not successful. At all times fetching mail has not been a problem. I did all the standard checks which did not make any difference: the server settings; addons disabled; virus checker disabled. Removed an account and re-added; deleted SMTP server settings and re-added. Proxy settings; and so on. On my old mac running version 128.14 no problems at all. I compared settings. Could not see any differences. On the new mac, created a new user, and new thunderbird profile. Added 1 pop3 account only. The problem was exactly the same. So it was not a profile issue. Decided to revert back to older version 144. PLEASE could Mozilla add a facility to Thunderbird to allow you to use existing profile rather than going through the operating system to get it to use my existing profile. I did get the old 144 version to use my 147 profile. After testing yesterday and today it all appears ok. I can send more than email at a time both from the same account, and from different accounts. What I do notice is it does seem to be slow on making the connection on some accounts. Most of the accounts are from the same host but the connection speed for sending is variable across the accounts from the same provider. My email is purely the words testing and testing in the body so not large. Is that to do with the space I have assigned to email mailbox at the provider side? One other issue with 147, and do not know if it is connected or a new feature of 147 and that is not being able to directly amend dates in tasks? In the newer versions of Thunderbird I found that I can only amend the date of a task by using a popup calendar and choose the date. In version 144 I can now amend the date of tasks by typing in the date field. Is it a feature / setting of 147 or a bug?