As you'll see from the following image, my copy of nautilus is a little broken.
I've lost access to all menus other than "file", there are black spots on the top corners of the window, and the file/folder icons are much larger than they were previously.
For reference, here as an image of how nautilus used to look (and how I'd like it to look!)
I think this has happened because I recently installed budgie as an alternate desktop. Other possible causes: I recently installed dropbox, and I also recently installed another alternate desktop (xfce4).
Attempted fixes so far (followed by system restart):
Purge Dropbox, Bugie, Xfce and Thunar:
sudo apt-get purge dropbox budgie-desktop xfce4 thunar sudo apt-get autoremove
Run Unity and Nautilus in separate sessions:
setsid unity setsid nautilus
Preferred applications > Utilities > File Manager > Nautilus
sudo apt-get --reinstall install nautilus
So far, nothing has worked.