Outlook 2010 cannot send reply because of format

I have a user that just received a new laptop and after setting up outlook 2010 for the first time, he begun having issues when replying to emails. It turns out that the 'to' field when replying has < user@domain.com > (without the space of course) and he can only then send the reply if he removes the < >. The error that he gets if he does remove the < > is "The operation failed. The messaging interfaces have returned an unknown error. If the problem persist, restart Outlook. Cannot resolve recipient"

I have tried creating a new profile and that had no effect. I am looking for any solutions to resolve this.

Thanks