Update status field information (34) is associated with a computer file (32) indicating the update status of a scanner (30, 40, 42, 44) that has previously scanned that computer file. A current scanner encountering that computer file again may examine the update status field information to determine if they match, if the update status field information does not match, then this indicates that one of the scanners concerned is out-of-date and an appropriate alert message relating to this out-of-date scanner is then generated and issued. The update status field information includes a scanner product identifier, a machine identifier, a scanner engine version identifier and a driver version identifier.