If you are using Outlook 2010 and Exchange 2010, you may have experimented this.
Your mailbox name show on top of your mailbox folders tree is showing your email address instead of your display name.
After doing some research, I found nothing which could explain that, except maybe the autodiscover process.
Indeed, the autodiscover process is resolving the email address, what ever you enter the email address, your windows account or your display name.
I also discovered this seems occurring ONLY for user account which exist before implementing Exchange 2010. I’m not really sure about that but it’s what I found. New account with mailbox created after Exchange 2010 deployment are showing their display name.
Starting from here, I checked the attributes of both user account – one with the ‘email address displayed’ issue and a ‘normal’ one.
I found that 2 MS Exchange attributes where not set for the account which has the issue:
So I set these attributes with the display name and it worked.
As this implies attributes modification, I warmly recommend to test it before and perform operation carefully.