OfficeScan 10.6 Administrator's Guide - Trend Micro™ Online Help

Trend Micro OfficeScan 10.6 Administrator’s Guide
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The cache for a threat-free file expires to prevent the exclusion of infected files from
scans, as illustrated in the following examples:
• It is possible that a severely outdated pattern file may have treated an infected,
unmodified file as threat-free. If the cache does not expire, the infected file remains
in the system until it is modified and detected by Real-time Scan.
• If a cached file was modified and Real-time Scan is not functional during the file
modification, the cache needs to expire so that the modified file can be scanned for
threats.
The number of caches added to the on-demand scan cache file depends on the scan type
and its scan target. For example, the number of caches may be less if the client only
scanned 200 of the 1,000 files in a computer during Manual Scan.
If on-demand scans are run frequently, the on-demand scan cache file reduces the
scanning time significantly. In a scan task where all caches are not expired, scanning that
usually takes 12 minutes can be reduced to 1 minute. Reducing the number of days a file
must remain unmodified and extending the cache expiration usually improve the
performance. Since files must remain unmodified for a relatively short period of time,
more caches can be added to the cache file. The caches also expire longer, which means
that more files are skipped from scans.
If on-demand scans are seldom run, you can disable the on-demand scan cache since
caches would have expired when the next scan runs.
To configure cache settings for scans:
PATH: NETWORKED COMPUTERS > CLIENT MANAGEMENT
1. In the client tree, click the root domain icon
specific domains or clients.
to include all clients or select
2. Click Settings > Privileges and Other Settings.
3. Click the Other Settings tab and go to the Cache Settings for Scans section.
4. Configure settings for the digital signature cache.
a. Select Enable the digital signature cache.
b. In Build the cache every __ days, specify how often the client builds the
cache.