This would be a bug with CCleaner v2.10 and with Firefox 3.0 when you view sites some times urls are not found now with urls that are not found some times they go over here on top click History, then - Show All History, now you have a box that pops open that says Library now at the bottom you will see something that says Unsorted Bookmarks now them sites that get placed in there they do not get cleaned as you will see them urls in your drop down Address Bar all the time witch is annoying they just build up and you just keep seeing them with all other sites you go to