CCleaner & Firefox
Not sure where to put it so its here, feel free to move if necessary.
I have been running CCleaner and Firefox for years but recently when I ran it I lost some of my bookmarks in Firefox. I could not explain it and found that in Firefox I'm on v21) you can restore your bookmarks as it seems to take periodic backups of them.
Just run CCleaner again toady and aload more disappeared, restored them and managed to find this article online, so a heads up if you are on CCleaner 4.01 I would upgrade to 4.02 as I have just done today and see how it goes. May be worth doing a manual backup before you next run it and see what happens.
Will post back if this doesn't fix it with the upgrade.