I'm sorry to inform you that those emails are gone from that file. If you have a Pop mail account and you left copies on the server, you could get them downloaded again. Otherwise you would need to use a backup. Emails are downloaded and stored in eg: Inbox mbox file. one after the other in the order downloaded. They are not stored as individual files. When you delete an email, the relevant section of that file is 'marked as deleted' and becomes hidden, but it is still in the same file. Yes, I did say 'file' not folder. When you compact the Inbox, it looks for those 'marked as deleted' emails and removes them, thus freeing up space and tidying the file. So what went wrong? Your mbox file must have been corrupted and TB could not locate the end of a 'marked as deleted' email. The 'Inbox' gets a lot of activity, so that 'file' is being constantly added to, modified with eg: 'marked as deleted' or 'marked as Junk' etc. So it is advised to use the Inbox as an Inbox for incoming mail and not as a general storage. Think of it like an office, you have incoming and outgoing tray for handling specific eg: letters, but you do not store them in the incoming tray, they would get filed away in a cabinet maybe under the client name. So create folders to organise emails. Compact the Inbox on a regular basis and keep it low in email numbers. Empty Junk and compact that folder on a regular basis. Please read info on Compacting: * http://kb.mozillazine.org/Compacting_folders Please read info on how to maintain a healthy Thunderbird. * http://kb.mozillazine.org/Keep_it_working_-_Thunderbird