Is he using the accessibility option? Method 2 here: https://support.microsoft.com/en-us/kb/2023257
Another thing worth checking is the User agent string in his IE, as explained here: https://support.microsoft.com/en-us/kb/2866064
Technology Tips and News
Is he using the accessibility option? Method 2 here: https://support.microsoft.com/en-us/kb/2023257
Another thing worth checking is the User agent string in his IE, as explained here: https://support.microsoft.com/en-us/kb/2866064
Exchange 2013, CU6, Outlook2010 Windows7 IE10 Catched mode
One user can't access default premiur OWA, it's only light mode.
CAS server setting is configured not to select OWA light mode, it's default.
Any solution on client side?