Hi Deb, Each "Mailbox" has an index file which allows for rapid sorting/searching of the text messages within the Mailbox folder. Occasionally this file, like any file, can become corrupted causing strange behaviors - double messages, disappearing messages, wrong message counts, etc. If you select the folder in the Mailboxes pane and choose Rebuild Mailboxes form the Mailbox menu, this index is recreated from scratch. Anytime you start having strange behaviors with message sorting, display, or other issues, it's a good idea to rebuild the mailbox. Hope this helps, Norm On Sunday, August 17, 2003, at 05:52 PM, Deb Hagen wrote: > What does "Rebuilding Mailbox" do exactly? When would I need to use > it? Thanks. > > Deb Hagen Norman Cohen nacohen at mac.com