I think that I may have an answer. Mine change to purple after I have read them. But under Tools, Internet Options, General - about 2/3 down the box there is a section on Browsing History. I have a check mark in the box indicating that I want my browsing history deleted when I exit IE. I do this because I don't want it slowing down my computer by saving all sorts of 'temporary' stuff. When I next open IE, the files are back to the original color; the program/computer doesn't where it has been the previous time. Hope this helps. If you don't want the browsing history deleted when you exit IE, uncheck the box.