A system for scanning computer files for unwanted properties, such as containing
computer viruses or being spam e-mail, allocates a priority to pending scan requests
based upon the identity of a computer user associated with the scan request. In
the case of a normal file access request, the computer user associated with the
scan request may be the file access request or in the case of an on-demand scan,
then the computer user associated with a particular scan request for a computer
file may be the owner or creator of that computer file. In the case of scan requests
associated with e-mails, the sender or recipient computer user may be used in the
allocation of a priority level for the scan request.