- go to windows file explorer, assuming you use windows - locate the profile folder - the message folder would be in the Imapmail folder for IMAP account, or the Mail folder for POP - ignore the .msf files - open the desired folder in notepad and search for the message with the pin. - the profile is at c:\users\<yourid>\appdata\roaming\thunderbird\profiles\<your profile name> - the profiles.ini text file in the thunderbird folder will identify the profile folder