Hello, it is a small case, you can try these:
( 1 ) Restart your Mac.
( 2 ) Disable stacks. Finder > View > Turn off Use Stacks then click Sort By > None.
( 3 ) Use some effective tool to move like iBoysoft MagicMenu.
- Download, install, and open it.
- Right-click the folder or file you want to move, and choose Move To. (The default folder path is the common ones: Downloads, Documents, Movies, Pictures…You can add other folder paths in it)
( 4 ) Change the file's permission.
( 5 ) Create a new use account.
Also read: Copy and Paste Not Working on Mac.
