Among the issues some people have had with OS X 10.9 Mavericks, one of the biggest gotchas was a loss of access to SMB network shares -- the connection some NAS devices (Network attached storage), Windows PCs or Linux servers use to provide file sharing.
In my case, I got the double foul. My NAS tried to mount forever and failed; same with a Windows 8 PC on my network. The cause appears to be changes made in the networking stack made by Apple. Apple's SMB2 implementation doesn't work with a lot of SMB2 devices -- even networked drives from Windows machines.
One easy fix involves changing a little bit of text in your server connection URL. Here's how it works: In the Finder, choose the "Go" menu and select "Connect to Server" (command-K). Type "cifs://yours
