When creating a new schedule or using an existing schedule to perform a master or differential backup of the server that will not include the active database, a number of files that are specific to the Microsoft Exchange server must be excluded.
When creating a new master or differential schedule, be sure to exclude all files with the *.edb or *.stm extension. Additionally, when modifying an existing master or differential schedule, be certain to modify the schedule to exclude all files with the *.edb or *.stm extension.