From IObit:

Often when we try to delete a file or folder in Windows, we see annoying messages like “Cannot delete file: Access is denied” or “Cannot delete folder: It is being used” This is majorly because the file or folder is being used by another program or user. IObit Unlocker is an ideal tool for such conditions. It releases the file or folder from being occupied by programs and allows you to quickly remove or modify the file or folder.