Delivere all new emails to In box

Then you have to change your filters/ rules :-) '''Anytime you told''' Thunderbird to sort your email from this contact or domain to a specific folder. Or something like that - Thunderbird has a lot of possibilities (settings) for organizing your mails. This is he doing now. Maybe it's helpful to look for a kind of muster (are the misguided mails from the same person/ in a date range/ marked with priority/ ...), or you ''check simple the rules/ settings''. Without further information I'm sorry not to help you more.