Rebuild Crew Log - when selected will recalculate the Flight Log entries and re pull the times from the verified flight log. This will not affect any user created entries or entries that have been created from the Training Module. It is important to rebuild the logs if you have to amend a verified flight log and change any crew time details when doing so.
Rebuild for All Crewmembers - when checked this will rebuild the crew log for all crewmembers that are listed in FOS.
Rebuild for All Dates - when this option is checked the logbook will re rebuild for all dates regardless of the date of the logbook entry that has been selected in FOS.