The default forms based login for OWA (Outlook Web Access) on Exchange 2010 requires users to login with the username in ‘DOMAIN\Username’ format. Show stopper for most of our users – they just type thier username on its own every morning, and won’t read the instructions. If you’re running in a single domain, you can set the default domain using the Exchange Management Console.
Navigate to ‘Server Configuration’ > ‘Client Access’, select your client access server, then the OWA tab below, right click on your OWA entry then view the properties. In the authentication tab of this window, you can select the logon format… Select username only, specify your domain, click ok – you’ll need to restart IIS for the change to come into operation.
Or you can do it even more quickly with the Exchange PowerShell:
Set-owavirtualdirectory -identity “owa (default web site)” -Sign-inFormat UserName -DefaultDomain “Home.local”