Messages may not be scanned when Exchange is moved from one cluster
node to another
When the Exchange cluster groups are moved from one node to another while the product is running in an Active-Passive cluster environment, the F-Secure Anti-Virus for Microsoft Exchange service can be down for a short period.
While the service is down, some e-mail messages may not be scanned on the transport level. However, all e-mail messages and attachments are scanned without interruptions on the storage level.