When I have a excel file open and I want to copy text of 1 cell to another file, Opus creates a clipboard.txt and I cannot get any pasted text to the other file?
You've probably done something which turned Ctrl-V into a global hotkey. (e.g. Turned the toolbar with the Edit menu into a floating toolbar.)
Go to Settings > Customize Toolbars > Keys, then push Ctrl-V into the filter at the bottom and see what it says about related hotkeys.
Yes, thank you, both ctrl-v and ctrl-c.