I have a 2TB Western Digital NAS which, until recently, has worked with my Mac (2013 Mac Mini, Mavericks 10.9.3, 16gb RAM) without a problem. I keep all the media for iTunes and a Roku 3 (which talks to Plex Server on my Mac) on there. It mounts from the network as /Volumes/Public. I am currently finding that whenever I leave my Mac for a few hours - say I go to work for example, or go to bed - that when I come back to it, it has dropped the volume. If I open Finder (which, if the drive has disconnected, seems to take anything up to 30 seconds to actually appear), the drive still appears under the Shared section of the sidebar. If I click on the drive the share appears, if I double click on the share it re-establishes no problem. A few hours later it will be gone again. I've tried re-setting all network settings and created a "Home" location instead of using Automatic but this doesn't seem to have helped. I don't have any settings to allow the computer to sleep - my monitors go off but the computer stays awake. It also doesn't matter whether I connect to the drive through AFP or SMB - same problem. I'm actually wondering if my Mac is dropping off the network altogether and losing the NAS is just the most visible symptom - but surely it should automatically reconnect if this happens? Any suggestions would be appreciated.