By default, HES/HES - Inbound Filtering does not store or archive emails. All messages are processed and immediately passed through to the customer's MTA, except when the receiving mail server becomes unavailable.

When the receiving mail server is down, HES/HES - Inbound Filtering will maintain up to ten (10) days for version 2.x, and then subsequently delete them.

If the customer email system becomes unavailable, thus preventing the service from delivering emails to the customer, the inbound message stream is automatically queued. Trend Micro will store the inbound customer email 10 days for version 2.0, or until the customer email system becomes available—whichever comes first. When the customer email system starts to accept emails again, the service will deliver emails with intelligent flow control to assist downstream manageability and to avoid inundating the customer email system.