Issue
Briefcase or Briefcase Attaché wont open. The user receives the message:
Resolution
Launch FileMaker and Select the File Menu
Select Open Remote
Select the Host and Open Briefcase
Prevention
If you are working with Briefcase from a hosted server the likely issue is the servers IP address has changed. To prevent this type of problem occurring in future server IPs should be static. Once this is done you can create a new shortcut, see the support article for Connecting Users from more information.
http://support.getbriefcase.net/entries/47012818-Connecting-Users