Troubleshooting spontaneous logout (window server crash?)
In the case of GoTo Meeting, it turns out there is a driver issue on MBP Retinas that have upgraded to Mavericks.  


  Machines and Cards Affected:
  
  
  MacBook Pro Retina 2012 (NVIDIA GeForce 650M) running Mac OSX 10.9 (Mavericks)
  MacBook Pro Retina 2013 (NVIDIA GeForce 750M) running Mac OSX 10.9 (Mavericks)  
  
  
  Symptoms
  
  
  Mac totally frozen, webcam light on. Hard reboot required to recover.
  Mac goes to login screen; logging back will show you the starting panel, but no control panel.
  When a new session is started, you will be asked to terminate the session you were previously running.
  
  
  Workaround #1: Upgrade to GoToMeeting 6.0, build 1259.
  
  
  Prevents GoToMeeting from dynamically switching between integrated and discrete video cards on session start.
  Hides webcam viewer for Presenters who are screen sharing with affected machines and cards.
  
  
  Workaround #2: Prevent OSX from dynamically switching between discrete and integrated GPUs.
  
  
  Download gfxCardStatus, available here.
  Unzip and run the application.
  Click the 'd' icon in the menu bar.
  Select Integrated Only from the menu.
  When finished with a GoToMeeting session,  select Dynamic Switching to restore normal use.
  
  
  Note: Using multi-monitor configurations will force discrete GPU usage and neither workaround will avoid this. [Source]