Try this:
To reduce the size of the database transaction log file :
1. Log in to the Symantec Endpoint Protection Manager.
2. Click Admin and select Servers.
3. Select the localhost under Servers.
4. Under Tasks, Select Edit Database Properties.
5. In the General tab under Database Maintenance Tasks.
6. Select the checkboxes next to Truncate the database transaction logs and Rebuild Indexes.
7. Click OK to apply the changes.
It will make changes to the database on the mentioned time under "Scheduled task". To reflect the changes immediately click on Truncate Database Transaction Log Nowand Rebuild Indexes Now under Tasks.