When you display the login page in Internet Explorer 11.0 you see the following missing checkbox icon:

It should actually display the following:

Another indication is that the popup calendar control is missing its arrows:


The cause of this issue is that IE had gone into a special security state, in which the font downloaded needed to display the icons has been disabled by the web browser.


Change the Custom level of the "protected Mode" - you can find that in the Security Tab of the Internet Options Menu.

After you click on the "Custom level..." Button you have to search for "font download" and change it to "enable".