As a long-time vim user and evangelist, I have grown to love tmux over the past year. A co-worker introduced it to me while my office workstation was still running OSX because iTerm2 has special tmux support.

My terminal session occasionally loses track of my tmux sessions when I log in via SSH while working remotely.

I found the following answer on Stack Overflow: http://superuser.com/questions/279169/tmux-died-and-says-no-sessions-is-there-any-way-to-recover

TL;DR: tmux needs to be told to recreate its socket files.

killall -10 tmux

Works like a charm.