Qt: Session Management Error

In bash you can do

export -n SESSION_MANAGER

I suspect you have an old session being saved by your window manager (typically GNOME or KDE) that still references the previous hostname (dev3).

Disposing of that session file might solve your problem. Under KDE these are stored in "~$USER/.kde/share/config/session/". There are also directories based upon hostname in ~$USER/.kde/(cache|socket|tmp)-$hostname which you can delete the old ones for the previous hostname. I'm assuming Linux/BSD platform for directory paths, adjust as necessary for other platform targets.

I'm not sure of GNOME session file placement. find ~$USER/ -name "*session*" might be a good start.