Default Profile location: C:\Users\<Windows user name>\AppData\Roaming\Thunderbird\Profiles\<Profile name>\ The AppData folder is folder is a hidden folder; to show hidden folders, open a Windows Explorer window and choose "Organize → Folder and Search Options → Folder Options → View (tab) → Show hidden files and folders". Emails, if stored in mail accounts, are located in mbox files. mbox files have no extension. emails are written to the file in date order, so oldest is at the top. '''If mail account was POP:''' click on 'Mail' folder click on pop mail account name folder. If deleted emails were left in 'Trash': open trash mbox file (no extension) using a text editing program like 'Notepad++' or another suitable text editing program that can handle the file size. If the emails were deleted, but you did not compact the folder to remove all marked as deleted emails then may still be in the original file eg: Inbox open Inbox mbox file (no extension) using a text editing program like 'Notepad++' or another suitable text editing program that can handle the file size. If you are talking about a subfolder then look for an *.sbd folder as it may contain mbox files. '''If mail account was imap:''' click on 'ImapMai'l folder click on imap mail account name folder. If you selected options to keep messages for the account on the computer and synchronise all messages locally so they could be viewed in offline mode, then an mbox file would have been created. You can open that mbox file using 'Notepad++' or another suitable text editing program that can handle the file size.