File with a .XLB extension contains all user’s custom Microsoft Excel bars, used to create spreadsheets. Data contained within such files enables transfer of custom bars between PCs and it is typically stored in the default directory: C:Documents and Settings[username]Application DataMicrosoftExcel for a given Windows user.

Information contained within a .XLB file may relate to visibility of certain bars and tools encompassed within them, or their position in the program’s window. MS Excel users can edit bars via View – Toolbars menu.