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VirusScan Enterprise 8.8 fails to install if there are UNC shares included in the PATH environment variable
Technical Articles ID:   KB71200
Last Modified:  3/2/2015


McAfee VirusScan Enterprise (VSE) 8.8



You see the following error when you try to install VSE 8.8:

McAfee VirusScan Enterprise does not function if there are UNC shares included in the PATH environment variable


One or more environment variable statements (User or System) contain UNC paths (for example, \\<computer_name>\<folder_name>). In most cases, the UNC path is redundant or was added by an older application.

During startup, Windows automatically uses the runtime search PATH to locate modules that are required to run applications and services. If the location is not immediately accessible, Windows might not be able to start certain services including VirusScan components such as McShield or vstskmgr.


UNC path statements are not supported in this context. However, the VSE 8.8Patch 1 Repost addresses this issue.

NOTE: The Repost will still block installation if this scenario is detected. However, the administrator is now able to override this behavior with the BYPASSUNCCHECK=1 option that can be specified via the command line. When specified at install time, this option bypasses the UNC check, allowing the installation to complete successfully. For example:


(where /q signifies a silent installation)

VSE 8.8 Patch 11 is the latest patch available from the Downloads tab on the ServicePortal at https://support.mcafee.com/downloads.

NOTE: VSE 8.8 Patch 11 supports all supported Windows operating systems.


Remove the UNC path statement from the Environment Variables statements. To access the Environment Variables, click Start, Settings, Control Panel, Advanced, Environment Variables.

For more information on supported Environment Variables in Windows, see: http://technet.microsoft.com/en-us/library/dd560744(WS.10).aspx.

NOTE: This is not supported in Windows 2008 Server; see Microsoft KnowledgeBase article: http://support.microsoft.com/kb/978856.



  • This workaround is not endorsed by McAfee because it involves modifying the .MSI installation file in an untested and unsupported way.
  • Editing the .MSI table using the Orca tool is advisable only for those competent with the technology.
  1. Download Orca, the Microsoft .MSI Editor, from: http://support.microsoft.com/kb/255905.
  2. Open the .MSI file in Orca and locate the row in the LaunchCondition table where the condition is UNC_PATH <> “TRUE”.
  3. Change the field content to 1.
This causes the condition to succeed every time and ignore the UNC_PATH variable.

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