I'm trying to run an update for bridge CS6 and the dialog keeps telling me to close bridge first even though Bridge isn't open
Yes, as John said, it's running in the background. On a Windows system (not sure if this is the same with Mac), if you close bridge by clicking on the "X" in the upper right of the window, it will not fully close Bridge. You have to exit Bridge through the main menu.
Thanks for your help. Problem solved