Hello,
Sorry to hear you are having issues. What Stardock software you're referring to? And more informations on your problem. A screenshot of what you're seeing ie. error popup etc will also help us help you.

Thanks
Basj,
Stardock Community Assistant.

If you're asking why you can not change the Start Button. That is because you have taskbar at Center of taskbar, which Custom Start Button don't work in that state. My guess is this due to Windows 11 limitation on Centered Start Button.

Thank you,

Basj,
Stardock Community Assistant