I have a file "Inbox" (no extension), that contains 41,707kb = 40,7mb, while all my Local Folders (Inbox,Unsent,Drafts,Sent,Trash) are EMPTY, because I cleaned them myself. 40,7 MegaByte doesn't sound empty to me and this file seems to grow every day. The complete path of this file is : C:\Documents and Settings\Erik\Application\Data\Thunderbird\Profiles\7hrs4k32.default\Mail\Local Folders\Inbox Keep in mind that the folder "Application Data" is hidden. Is there a way to clean this file "Inbox" via some setting or function in Thunderbird ? Thank you in advance. EDIT : Found a solution. Case closed. Pffft.