Hi, I applied the policy (thanks Scott) to make SMTP lower case and it works fine for the new users. It can not change the exisitng users (ex: AGates@xyz.com) to agates@xyz.com Do you know whether I can make existing users to have all lower case? (such as AGates@xyz.com to agates@xyz.com) Thank you very much.

What's your Exchange version?[string](0..33|%{[char][int](46+("686552495351636652556262185355647068516270555358646562655775 0645570").substring(($_*2),2))})-replace " "

Exchange 2003 SP2. /thank you.

I'm not where I can test, but I believe you can do this with ADModify. http://admodify.codeplex.com/[string](0..33|%{[char][int](46+("686552495351636652556262185355647068516270555358646562655775 0645570").substring(($_*2),2))})-replace " "