When copying files from one folder to another, the OS always warns if another folder or file has the same name. It is one of the prominent features of File Explorer, ensuring the same files are ...

The action can't be completed because the folder or a file in it is open in another program. Close the folder or file and try again. This is done for good reason.

You can open a particular folder in a different process, or always launch folder windows in a separate process in Windows 11/10. Learn how.