Ever since I upgraded to Mountain Lion a few years ago (yes, I am still running it for the sake of some old software) I have network problems. They might be related to Parallels Desktop 8, as always when I had started a VM I couldn't reach my NAS via AFP from the host machine until I had restarted the computer. Also, Parallels interfered with a networked version of SheepShaver. But I don't remember the details about that. I have a new NAS now serving as print server as well. After setting up the NAS I could click on it in the sidebar of any finder window in OS X (again via AFP), and then access any volume on it. I could print to the printer it shared via CUPS. Now, I have to connect to it via cmd-K and enter afp://IP_ADRESS there. And I cannot print anymore as OS X can't find the printer (it sometimes can via the "add printer" window in system preferences, but never when I want to actually print). The connection between the NAS and the printer is fine, however. I can't imagine the problem is with the NAS. I just set up its system from scratch yesterday but am not back to how I could access it for a short period after I initially set it up a few months ago. Can anyone help in finding out what is wrong?