When I edit a file in Emacs on my Ubuntu Linux system and try to save, I sometimes see the message:
File foo.txt has changed on disk. Really save?
The weird thing is that I haven't changed it on disk, I'm just editing it in Emacs and nothing else. I've saved it myself a minute ago and that should be its last state. So some other process must be touching it behind my back, while I'm editing it.
Of course I can tell Emacs to save anyway, but I'm just curious why the file has allegedly changed without my knowledge.
Does anyone know this problem? What is a likely cause? Or is it possibly an Emacs bug?