I was going through a new WP install and thought of changing the permalinks for the pages.

http://www.domain.com/contact/

seems better to look at than this,

http://www.domain.com/?page=5

So, I set, /%postname%/ in the custom field.

Looking at the page on IE, it produced results such as (1) page loading slow, (2) page not found, or (3) a background color on certain parts of page that is not supposed to be there.

Checking it with other latest browsers such as FF, Chrome and Opera and all was fine.

S, I just set it without trailing slash like this, /%postname%, instead. IE seems to take it without any weird behavior on the page going on.