From For Your Information Technologies:
Free Synchronize is a complete file and folder synchronization software application that can be used to quickly and easily get the latest files from the source location copied to the destination location, without going through a timely file backup process. All settings in this application can be saved as a named configuration. This is especially useful if you have several different drives or folders that you need to synchronize. Once the current configuration is named and saved, it can easily be restored by selecting that configuration name from the drop down. Safe mode is designed to make sure nothing gets changed or deleted from the destination location. Only files that do not currently exist in the destination will be copied. Even if the file is newer in the source location, it will not be copied. Normal mode is the most standardized way to synchronize files. It will copy files from the source location that do not exist in the destination location. But, this mode will also copy over any files that have been changed as well, assuming the last modified date of the file in the source location is newer than the modified date of the destination file.