Comment 8 for bug 876999

I think the key is that this seems to be related to a problem in how VirtualBox 4.1.4 works on a Mac to host a Unity guest. This is not a problem in my normal installation of Ubuntu. I don't know why it only appears to be affecting the Mac version of VirtualBox. However, I suspect that the nautilus crew would say that the problem lies in how VirtualBox on the Mac handles their program. The onus would therefore be on VirtualBox to fix whatever problem there might be.

In my limited experience, it seems that VirtualBox has been having problems with Ubuntu Unity since late in 11.04 on the Mac.