If you have a email system and configures clamscan.exe as your external virus scanner for emails, the clamscan.exe will be initialized for each mail.
This means that each mail will take perhaps 10-20 seconds to scan. perhaps 18 seconds to load all virus definitions and then scan the mail.

Is there any way of having clamscan.exe (or other exe) to be always running, so that the definitions are only loaded once.

I need the definitions already loaded, even if I call "clamscan.exe <filename>"

// Robert