Back Up software

I need a Cross platform small Backup & restore App built around the Default O/S locations used by a widely available Software Program - The built program needs to be able to access specified folders & file types that have been already installed. ( XML) The software is available on BOTH Windows & Mac platforms ( as security copies- user backups etc solely - - its for safety copies- backups - default folder contents restoration after formatting - Restoring on a new machine etc ) . . No modifications of the backed up files are required, Mainly for Archive purposes. The program I require building is designed for for backing up certain directory contents or individual Files ( XML etc) associated with the already installed cross platform Program.. NO modifications of the files are required. The Program I require is simply backing up OR restoring USER & default folder contents & related file types for the Program. The program needs NO specific access to the Program itself, or indeed any interaction, but to simply be able to save & restore personal user folders - security copies etc - as & when required by the user.