''<p>johnbluck_33 [[#question-1403468|said]]</p>'' <blockquote>Thunderbird is deleting messages from my sent and trash folders. Can this be stopped? </blockquote> Quite possibly not. Most folk use IMAP protocol to get their mail and this protocol is syncronised to the server. So if your mail provider has a policy of say deleting junk after 7 days and emptying the trash every 14 days then this will be syncronised to Thunderbird. WHat if any options your mail provider offers with regard to opting out you would have to check with them. Having said that Thunderbird has it's own settings in account settings > syncronization and storage which you could check. But server side settings will override Thunderbird's when it comes to deletions. Users of POP accounts have no local retention settings at all really. Mail in pop accounts stay where it is put until you act on it. <blockquote> I would like to keep messages in my sent and trash folders until I delete them. </blockquote> You may or may not be able to do that, depending on how your account is configured and the retention options your mail provider offers.