I set up a friends email account on his new Mac and I noticed that the mail window did not have the familiar Trash - On My Mac and the Server. His mail box is apparently full and we can't find a way to empty it. Has this interface changed? Can anyone tell me the fix. This is a bit urgent now.

In Mail, go to Mail>Preferences>Accounts>Mailbox Behaviors and make sure "Move deleted messages to the trash mailbox" is checked. This should create the trash folder in the Mail sidebar you're looking for. If your friend has more than one email account set up in Mail, do this for each one and hit "Save" when switching to each account (it'll pop up so you can't miss that step).

Another thing you can do is right-click on each of the folders he has in the Mail sidebar and select "Erase deleted messages..."

Hope this helps!

Thanks, actually I had discovered this but you reply expanded on it, I will see him again soon and we will go over things again. Although I still did not see the flyout on the side of the Trash Can which reveals two more little Trash Cans each marked On My Computer and Server Name as I do on my computer, perhaps this feature is no longer exixts. I find it most usefull to click on either on of the two little cans and see what's there to be deleted. Really there is no reason to go on about this I think the problem has bee solved, thanks.