Hi Hub,
Thanks for using Syncfusion Products.
If you are not published any of your own dashboards into dashboard server, Please follow the below steps to delete the samples data from Dashboard server.
1. Find the 'DatabaseUninstaller.bat' file from the below location.
C:\Syncfusion\Dashboard Server\Utilities\DatabaseUninstaller
2. Now all your database and resource files are removed from the Dashboard Server
3. Before doing application startup settings, navigate to the below location and delete the files from the folder.
C:\Syncfusion\Dashboard Server\DashboardServer.Web\SampleDashboards\
4. Now you can do the startup settings, and now the demo items cannot be loaded into Dashboard Server
Otherwise, you have to delete the Dashboards, Widgets and data sources manually from the Dashboard Server.
Regards,
Makila S.