This works with IMAP by default. But not with POP accounts ever.

Hi, thanks for reply, but isn't IMAP an ingoing protocol? I looked into thunderbird options and IMAP is only around POP. I'd like to synchronize outgoing mails in different devices.

Imap really means all the emails are stored on the server and you access the server from various computers to see the same thing. If you use an imap account and delete something it is deleted off server, so all imap account folders synchronise with server and show the deleted email removed from all views of server. All incoming and outgoing stored on server folders.

Please read some good info on imap.

• https://support.mozilla.org/en-US/kb/imap-synchronization

Advise you synchronise all folders to ensure full downloads and then periodically create a backup of profile because it maybe on server, but it is still only one copy on server. You cannot consider imap folders as a separate copy because folders synchronise with server.

Note: you cannot simply change server settings for a pop account to swap it into an imap account. You have to create a new existing mail account for email address and set it up as imap.

POP accounts can only access server Inbox and download copies. Pop account folders do not synchronise with server, so server views of emails can be very different from what is visibe in a pop account.

Some servers eg: gmail, know when you have used the smtp server for that gmail email address, so regardless of whether pop or imap, they will now automatically keep copies of outgoing emails on the server, so they are visible via webmail. But few servers do this.

Now that brightened it up for me, thanks. Still have a question though, if I disable a POP account, then create another one, and import my emails to a client, would those messages be deleted because they're not on a server, or a server will sort of import them from a client?

If the popped/previously downloaded emails are still visible via webmail, then they are still on server and so will get shown in an imap mail account.

If they are not visible via webmail account then the only copy is in the Pop mail account in Thunderbird.

However, if you get copies of any emails in pop account copied into 'Local Folders' mail account then those emails will still be visible in Thunderbird even after deleting the pop account.

In addition, you can then copy (not move ) those 'Local Folders' emails back into imap folders to get them put back on server - if you want, but do it in batches. Note this will use up some quota on server, but imap accounts are usually allowed a greater quota. I say 'copy' not move, because if something goes wrong then you will still have a copy in Thunderbird. You can always delete those 'Local Folder emails once you are happy they are visible via webmail, so you know they are on server.

But it may be helpful to keep old emails in the 'Local Folders' account and use it like an archive.

Thank You very kindly, I'll try that over the weekend. Fantastic!

To solve this problem, I set a bcc to my own email id & set a rule either on Server or on mail clients to move such BCCed emails to sent folder.