If your Vista or Windows 2008 Server has UAC (User Account Control) enabled, then web interface setup will not run unless you execute it with elevated rights, as an administrator.  You will need to do it even if you are logged in as a member of administrator group.

Normal executables can be executed with elevated rights by right clicking them, and selecting Run as Administrator, bu this does not work with Windows Installer (MSI) files, which is our Web Interface installer.

There are several ways of executing the MSI file with elevated lights.  One of the easiest ones is to save it in some directory, e.g. c:\temp, then click the Start button, in the Start Search... box type cmd, and press Ctrl - Shift - Enter.  The command window will open in the administrator mode.  Change to the c:\temp folder, and execute WebMailSetup.msi.

Sometimes there are problems, related to access rights to the folders under the web interface. The application needs to write into the App_Data folder in order to keep application settings, but default rights do not allow that because of very tight security of Windows Vista and later

The easiest way to solve problem is to enable impersonation with your WebMail application. To do that:

• run IIS Manager from Control Panel - Administrative Tools;
• In the Connections panel, navigate to the WebMail application in the folder on the web site where you installed it
• double click the Authentication icon under the IIS section of the middle panel
• Select ASP.NET Impersonation, right click it, select Edit, click Specific User, then click Set..., and specify the user who has full access to the App_Data physical directory, click OK;
• Right click ASP.NET Impersonation again, and select Enable.

In some cases, enabling impersonation will cause problems with so called Integrated Managed Pipelining mode. You will need to switch the WebMail application to the Classic .NET Application Pool... To do it:

• Run IIS Manager from Control Panel - Administrtive Tools;
• In the Connections panel, navigate to the WebMail application in the folder on the web site where you installed it
• Click Advanced Settings on the right panel;
• In the Application Pool field, change the value of DefaultAppPool to Classic .NET AppPool;