Uninstalling Elgato Game Capture HD software is a straightforward process.
macOS / OS X
Elgato Game Capture HD can be uninstalled like other OS X applications.
Simply drag the Game Capture HD application to the Trash, and the process is complete.
Optionally, you can also remove the com.elgato.GameCaptureHD.plist (Preference) file, by deleting it from the Preferences folder in your User directory.
1) Go the Finder, perhaps by clicking on your Desktop.
2) In the Go menu, select Go to Folder...
3) Type "~/Library/Preferences", then press the Go button.
4) Find the com.elgato.GameCaptureHD.plist and move it to the Trash.
5) Restart your computer.
Erasing that file, and then restarting your computer, will remove all of your Elgato Game Capture HD software settings.
Windows
Like other Windows applications, Elgato Game Capture HD can be uninstalled using Windows itself.
We have an article that covers the uninstallation process, with screenshots:
How to uninstall Elgato Game Capture HD software on Windows
Microsoft also covers this process:
Windows 7 and Windows 10
See this Microsoft.com article for more details about the uninstall process:
http://windows.microsoft.com/en-us/windows/uninstall-change-program#uninstall-change-program=windows-7
Windows 8
See this Microsoft.com article for more details about the uninstall process:
http://windows.microsoft.com/en-us/windows-8/uninstall-change-program