If you’re still seeing the ‘File in use’ message, then it’s time to take a closer look at exactly what’s running on your MacBook, by launching the Activity monitor app (‘Applications’ > ‘Utilities’ > ‘Activity Monitor).
Start by checking what apps you have open and closing any that you suspect might be accessing the file in question, then try deleting the file again. You’ll need to hunt down the culprit, and close it. If you’re getting a ‘File in use’ message whenever you try and drag a file to the Trash, that means an app or process is currently using this file. Problem: A file is being used by another app or process
