Comment 138 for bug 211631

Here's some info, if it helps:

Neither of the solutions on https://help.ubuntu.com/community/MountWindowsSharesPermanently#System%20Hangs%20on%20Shutdown or https://wiki.ubuntu.com/MountWindowsSharesPermanently#Fixing%20a%20CIFS%20bug%20with%20network%20manager worked for me (after one or two quick shutdowns, it was back to taking a minute to shutdown) However if I unmount my network drive before shutting down, my computer does in fact shut down almost instantly, as opposed to the one minute it takes if I don't.