I used this when for some reason a SQL Server Database would lose its permissions daily.
Create a batch file .e.g Change Permissions.bat with the following inside it.
cacls “D:\YOUR DIRECTORY PATH” /t /e /c /g “USERNAME – If its a Domain User domain\user”:F
Change your path and username you wish to add permissions to.
Please note: The above command pushes the permission to ALL files and folders below your given path.