System Settings : Advanced : File management
 
File management
FortiAnalyzer allows you to configure automatic deletion of device log files, quarantined files, reports, and content archive files after a set period of time.
To configure automatic deletion settings, go to System Settings > Advanced > File Management.
Figure 91: File Management
Configure the following settings:
Device log files older than
Select to enable this feature, enter a value in the text field, then select the time period from the drop-down list (Hours, Days, Weeks, or Months)
Quarantined files older than
Select to enable this feature, enter a value in the text field, and select the time period from the drop-down list.
Reports older than
Select to enable this feature, enter a value in the text field, and select the time period from the drop-down list.
Content archive files older than
Select to enable this feature, enter a value in the text field, and select the time period from the drop-down list.