检查freebsd7.x的邮件系统，发现/var/log/maillog提示：
MailScanner[36664]: ERROR: Malformed database
检查clamd的log记录，提示错误信息“
Not loading PUA signatures. ERROR: Malformed database”
如下：
tail -f /var/log/clamav/clamd.log
Reading databases from /var/db/clamav
Not loading PUA signatures.
ERROR: Malformed database
+++ Started at Tue Feb 7 14:11:38 2012
clamd daemon 0.92.1 (OS: freebsd7.0, ARCH: i386, CPU: i386)
Running as user clamav (UID 106, GID 106)
Log file size limited to 1048576 bytes.
Reading databases from /var/db/clamav
Not loading PUA signatures.
ERROR: Malformed database
发现clamav的版本还是老的版本0.92.1，此老版本已不支持现在新的database数据库格式了，所以报错，clamd进程也启动不了！解决办法就是升级clamav为最新的版本，目前是clamav-0.97.3，关于怎么升级，此处不再做介绍，请参阅本blog相关文章！