Connection to shared network server sometimes stuck connecting, needs restart to fix
I was having the exact same issue. In my case, both my mac and my nas were configured for jumbo frames. My new switch, however, even thought it supports jumbo frames, did not have jumbo frame support turned on. Knocking the MTU on the mac back down to the standard 1500 MTU (under advanced settings, and the advanced tab in network system preferences) got everything working again.