Outlook may hang when using McAfee VirusScan with 'On Access Scan' enabled


Client workstations using McAfee VirusScan may hang Outlook when the "On Access Scan" feature is enabled and Exclaimer is adding a disclaimer with a logo.


McAfee VirusScan has a vulnerability in it's use of the MAPI fields PR_ATTACH_FILENAME and PR_ATTACH_LONG_FILENAME which Exclaimer uses to store the details of the file used to hold the logo.
Exclaimer uses a fully qualified path in these fields, but McAfee VirusScan only expects to see an old DOS style filename (8.3) which crashed the McAfee client. This does not affect Outlook and represents a security vulnerability in the anti-virus software.


McAfee have a patch (Patch 10) that is available for supported customers. To access this patch, you will need the Grant Number provided during your purchase of McAfee VirusScan and you need to visit the Service Portal where you can download this patch.


If the Outlook client is restarted, the email can be viewed without problems. If the On Access Scan feature is disabled inside McAfee VirusScan, then the problem does not occur.


  • Exclaimer 3.x
  • Exclaimer 4.x
  • McAfee Virus Scan v8.0.0
Article ID: 20050420
Last Reviewed: 25th April 2005
Revision: 1.0