It is not sound hopeful. usually, this is the time you use your backup copy of your profile or recreate your IMAP mail account to see folders on server. Thunderbird Profile is stored in the Appdata/Roaming/Thunderbird folders, which is your responsibility for creating a backup. Usually, any tech guy worth their salt, would create a backup of anything they could access in the standard documents folders created for use by Windows OS and also anything in Appdata/Roaming as this is the standard default location for files used by non-windows applications. But they may claim that backups or rescue of anything on the computer prior to doing a complete reinstall is your responsibility or should be specifically requested. So, you could ask the tech-guy if they tried to rescue anything before wiping everything. If any mails were stored on the server, then you could get access to all those emails. POP mail accounts will download from the Inbox or use an Imap mail account to see folders on the server. For future use: Profile folder and backup information. * http://kb.mozillazine.org/Profile_folder_-_Thunderbird * http://kb.mozillazine.org/Profile_backup * http://kb.mozillazine.org/IMAP_backup