During a mailbox search, the service account copies
messages from the end user mailbox to the Exchange discovery mailbox
and then parses the search results to the ScanMail database.
This is a time-consuming and resource-intensive task. Trend Micro recommends
performing an estimate of the search results before performing the
actual search.
Performing an estimate of the search results does not require
the service account to copy any messages and has a limited impact
on the Exchange server. After performing an estimate, administrators
can optimize the search criteria before performing the actual search.
If administrators think a mailbox search may affect the performance
of the Exchange server, Trend Micro recommends
scheduling the search to run at off-peak hours using the Search
Later function.