A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
I think I've spotted where the problem can originate within Excel. I refer specifically to MrRogers83's original problem, not other points people have raised. I can generate it within Excel and resolve it (for the moment) in Excel. I'm using Excel 2019 on Windows 10.
If a cell is copied (shown with green dashes around it) when I close Excel, then my first Copy command next time Excel is started produces the error message. (I find that a second Copy instruction resolves it.) Any Copy can be cancelled by pressing Escape before leaving Excel. If Clipboard history is turned on, the situation seems to get more complicated.
I can see exactly when the clipboard is occupied by starting Clipboard Settings from the Start menu and watching the "Clear" button at the bottom. The word "Clear" turns grey whenever the clipboard is empty (since there's nothing to clear). So I can watch as Excel uses it and frees it. I advise turning Clipboard history off as it seems to make the matter more complicated.
I'd think that Microsoft could resolve this by ensuring that the clipboard is always freed (equivalent to pressing Escape) whenever Excel is shut down. A check on how Clipboard history interacts with this seems advisable too.