Dynamic backup

A safer solution would be to schedule a tine after shutdown and do the complete profile. You lose data otherwise beccause Thunderbird still has files open . That has been my experience.

Thanks - I'm well aware of doing backups while Thunderbird is closed down, but what I am seeking is whether it is possible to do regular backups e.g. at night without shutting down Regards Ron

Well, if the accounts are IMAP, there is no need, other than to make a backup copy of the profile when changing the profile, such as adding an account. For POP, you could test this by copying the profile while thunderbird is running and then restore from the profile. Regardless, I would be nervous about mbox files. BUT, there are persons on this forum with far more knowledge than I who could give better advice.

There are third party tools (not free) like Mail Backup X or Wondershare Ubackit that you can try.

Thanks - I'm well aware of doing backups while Thunderbird is closed down, but what I am seeking is whether it is possible to do regular backups e.g. at night without shutting down Regards Ron

It's not recommended, regardless of the backup tool used. (except Thunderbird's export)

But it's your data, so the risk is entirely on you.