Hi All. I have just installed V13 and the old Opus icon on the taskbar has disappeared when Opus is closed but returns when you open it. The desktop icon is also dark with a small tick box and an arrow.
Sounds like the taskbar icon just isn't pinned. Right-click it and use the option to pin it.
If it's all black, that's probably a shell icon cache problem. Try a tool that clears the icon cache to fix it. Either that or the shortcut on the taskbar has had its icon customised but what it's pointing to is no longer there.