My X-box keeps shutting down the file sharing. I start it, then a couple of hours later it switches off silently, often I don't notice until I try to connect to it (I use my X-box as a file-server at work, since my new computer (TiB) doesn't have that much hd-space).
When file sharing has switched off, the sharing-panel in System Preferences looks as it is supposed to: a label saying "File sharing is off", and a button, "Start". I press start and the label says "File sharing starting up..." and it doesn't. It has now been starting file sharing for four hours...
So I try to quit everything and log out. When I log in, sometimes filesharing is on again, sometimes not. So I quit everything again and restart, now file sharing is always on (if I tried to start it before I restarted).
Mac OS X should not require a restart. Mac OS X should not switch file sharing off silently and without reason.