An application update to version 3.45 has been made to address a serious bug occurring on Windows 64 bit platforms. If you are running Windows 64 bit clients, please cancel existing Rosetta@home jobs that are either cached or running the older 3.43 application version. You may see a blank Rosetta@home screensaver window which you should manually exit/close. We are sorry for any inconvenience and we are updating our scripts and process to prevent this from happening again in the future. For more information about this issue you can go to this message board thread. Thank you to those that have posted on this thread and have helped to identify the root cause of this issue.