Hi,

The Windows group "SIMATIC HMI" should be created automatically when installing WinCC Unified. However, in order to start the external program from WinCC Unified PC Runtime, you must manually go to the configuration of the logged-in Windows user account and add it to the "SIMATIC HMI" group. These steps are detailed in the FAQ:

Start external program with GUI from WinCC Unified PC Runtime

If you have any problems following these steps or get any error messages, please share it so we can help you.