could this issue be caused by contention as VirusScan and McAfee agent are doing a lot of disk I/O on the same file ?
Which version of Outlook, there are issues between Outlook 13 and DLP- if you have the scan email. Google DLP and outlook 13 and article should pop up.
outlook version 10.....
which issues are you talking about ?
Do you have a Cisco Email protection installed on the client PC?
Could you please share Outlook plugins on the client PC?