Synchronizer is a program for comparing and synchronizing directories, including subdirectories and files. It is particularly useful on mobile computers when installing new software and exchanging data. The features include file compare between directories, with or without subdirectories; intuitive display of sync directions with arrows and colors; filter options (i.e., all identical files); individual file selection for synchronization; sync function with selection of sync direction; printing of file list; executable from a command line with parameters as in batch files; and file exception lists.