When configuring the initial backup job, you may choose to apply an Inclusion filter against the content within the selected mailbox folders. This filter is based on the modification date of each item within the mailboxes and is designed to Include the content within the specified time period (by Date or by Range), not Exclude.
Please review the following scenarios to determine which setting is best for your backup needs. Please note that the initial filter configuration will impact how Updates (Full, Incremental, and Differential) are performed, so choose wisely.
Each configuration includes a chart displaying what will be included (green bar) versus what will be excluded (red bar). The bar on the bottom represents the initial Full backup and each above it represents the updates that can be performed.