I have a mid 2012 15" retina Macbook Pro running 10.9.4. I've had networking issues for a long time, possibly before I upgraded to 10.9. Hoping I can get some ideas on how to get it working like a fresh install, without re-installing. I can connect to my home LAN (wired & wifi), hotspots no problem. I can see some of my network devices (like Time Machine, or a PC or a Drobo), but only if I enter their ip address directly. This could be SSH, or just using the finder. My other Macs don't ever see this machine, and I don't automatically see my other machines under "devices" in the Finder like with my other macs. Another screwy issue is with Minecraft... i play together with my son a lot. I can host a game on a PC and connect to it, but only if I manually enter the IP address and port number. I have checked, re-checked, checked again the network settings in Network Preferences. It's on the right Subnet, has the right IP address, router, DNS entry. I have tried renaming the /Library/Preferences/SystemConfiguration when booted into the fresh install and then booting back into the primary, to eliminate any plist files in there that might be corrupt, but that didn't fix it. I did a clean install on a separate partition and I have no problems, so it isn't hardware. I am tempted to just reinstall, but would rather try and see if there is a configuration I can reset first.