I believe BA is reading HKEY_LOCAL_MACHINE\SOFTWARE\Cakewalk Music Software\Cakewalk\Installers\EE137A4A-E652-4652-9283-0DB37EC8849D from the registry to determine the status of CbB. When I remove this entry and start up BA I see the Update button instead of Open. A clean reinstall includes removing registry keys. The clean instructions for the last version of SONAR are published here. CbB works the same way except CbB should be uninstalled using BA, The registry entries are: