For the past couple months we have been seeing users that get challenged for credentials at times when their accounts are not locked and their passwords are valid. What we find when we connect to their system is that the reason for this is the dialog box had the wrong username. For example a new user today would get domain\firstname.lastname and then at a seemingly random time later the IE popping asking for proper credentials will havefirstinitiallastname or something else that they're AD account was never setup to. They can then choose to use a different account but not sure why or where it suddenly gets an incorrect userame from.
Most are running IE9 with some 10 and 11.
Just reaching out if anyone else has experienced this.
