When UAC is enabled on Windows Vista and higher, logon scripts that map network drives do not appear to work for users who are administrators on their computer. This is described in the Group Policy Scripts can fail due to User Account Control section of this TechNet article:
Deploying Group Policy Using Windows Vista
This happens because logon scripts run with an administrative user’s full token. The desktop then loads with the user’s limited token. The split token sessions do not share the view of network resources, so the mapped drives are not visible when the desktop loads. The workaround in the article above involves using a wrapper script, Launchapp.wsf, as the logon script. This deletes and recreates a scheduled task to launch the real logon script when the scheduled task is created. (The schedule trigger is whenever the scheduled task is created or changed.) This scheduled task is set to run as the logged on user and will launch in the limited token session. This will allow the drives to be visible to the user in the limited token session.
Unfortunately, an recent customer case pointed out an issue with using Launchapp.wsf. Launching a logon script in this way can cause the logon script to fail on shared computers, especially on machines where users who are administrators share the machine with users who are standard users. After an administrative user logs on and off, standard users will not have the permissions necessary to delete the schedule task and the script will fail.
To work around this issue, I have created a new version of Launchapp.wsf (attached below). I took the existing version of Launchapp.wsf and combined it with code from John Howard’s blog (http://blogs.technet.com/jhoward/archive/2008/11/19/how-to-detect-uac-elevation-from-vbscript.aspx). If this version of Launchapp.wsf detects it is running elevated, it deletes/creates the scheduled task as the original did. If it is not running elevated, it simply launches the app or script passed on the command line directly.
- Michael Murgolo, Senior Consultant, Microsoft Services, U.S. East Region.