I upgraded to the 78.0.1 (32bit) and then decided to return to my prior version (I guess 68.?). I reinstalled a 68.? version but had some problems error-[a newer version of Thunderbird may have made changes to your profile...] Then I decided to go back to the newest version 78.0.1 (38 bit). It created a profile. ini. I have my profile folder for the earlier 68.? version. I renamed it the same name as the new profile.ini file refers to. ''[Install 8216C80C92C4E828] Default=Profiles/jbj3qpd7.default-release Locked=1' So I called the profile ' jbj3pd7.default-release' And I found all my emails and folders and accounts as they were. But- my main account folder has a padlock on it and I cannot send or get emails. I worked out that if I change the Server settings/security settings/connection security from Starttls to 'none' in both incoming and outgoing servers then I can receive but not send emails. Sending gives me "an error occurred while sending mails, "the mail server sent an incorrect greeting + OK POP 3 ready mail 1500020e32". If I leave it as Starttls as it should be I cannot transmit any emails. I rang my email provider and they could not figure it out. 'Any ideas what I should do? Should I start with clean Thunderbird 78, and fill in account details and then how do I get the prior versions profile into it? Current profile .ini below- [Install8216C80C92C4E828] Default=C:\copy backblaze emails unzip Locked=1 [Profile1] Name=default-release IsRelative=1 Path=Profiles/jbj3qpd7.default-release [Profile0] Name=Default User IsRelative=0 Path=C:\copy backblaze emails unzip Default=1 [General] StartWithLastProfile=1 Version=2