The setup package is designed to detect an existing installation of Business Analyst Desktop. Products previous to version 10.6 must be uninstalled before installing Business Analyst.
Existing license manager users must uninstall previous versions of ArcGIS License Manager prior to installing the ArcGIS License Manager 10.6.
To uninstall Business Analyst use the Programs and Features dialog or the Add/Remove Programs dialog. The software and data are listed individually.
To find out what ArcGIS products are currently installed on your machine, download the PatchFinder utility from the Esri support site and run it from your local machine.