A system and method to efficiently back up files while preserving memory resources. The system includes a generation module to generate an unordered list of backup files and associated attributes, and a processing module to back up local files one at a time by modifying the backup files to reflect changes to the local files. The processing module may include a retrieval module to retrieve local file attribute information from the hard disk, a comparator module to compare the local file attributes to corresponding backup file information on the list, and an update module to update the corresponding backup file to reflect any differences. In this manner, the present invention avoids processing limitations caused by insufficient memory and/or excessive quantities of local files.