FreeFileSync is a folder comparison and synchronization software that creates and manages backup copies of all your important files. Instead of copying every file every time, FreeFileSync determines the differences between a source and a target folder and transfers only the minimum amount of data needed. FreeFileSync is free on Windows, Linux and macOS and has an Open Source version for Linux.

Donation version available with these extra features:
- Parallel file copy
- Auto-updater (Windows)
- Portable version (ZIP)
- Silent installation