Comment 4 for bug 842257

I'm pretty sure I know why this is happening and a work around to fix it. This happens when you're using a custom nautilus-home.desktop launcher such as one in your ~/.local/share/applications/ instead of the one in /usr/share/applications. Many instructions for adding quicklists have you copy the original launcher and modify it. This will break it. If you want to repair this you need to add your quicklists to /usr/shar/applications/nautilus-home.dektop and then execute unity --reset-icons. You will have to repopulate your launcher as it will be back to default (with your quicklists). Hope this helps,
Rekh127