Editor's Review
Manual copy-paste is an inefficient way to back up files. FreeFileSync eliminates the guesswork entirely. I set up a mirror sync between my work folder and an external drive, and it copied only new and changed files, leaving everything else untouched. The comparison preview showed exactly what would happen before I hit start, so there were no surprises.
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Beginner’s Quick Start Tips
Start with Mirror mode for your first test run. It’s the simplest to wrap your head around, and lets you nail down how full backups work before moving to more complex setups.
Always scan through comparison results before hitting sync. Double check deletions specifically — it’s way easier to uncheck a file now than recover it later.
Stick to Update mode for archival drives where you never want to remove old files. It adds new content without touching anything already stored there.
Save your sync jobs once you’ve got them configured. You’ll save a ton of time not reselecting folders and filters every time you run a backup.
The tool serves up four core sync modes to fit exactly what you’re doing, no lazy one-size-fits-all logic. Mirror mode creates an exact 1:1 copy of your source folder on the destination, wiping anything that doesn’t exist in the source — perfect for regular full system backups. Update mode only copies new or modified files over, and never deletes anything on the target drive, great for building out archival storage. Two-way sync pushes changes from both sides, resolving conflicts by picking the most recently modified file, ideal for keeping folders matched between two work devices. If you need granular control, Custom mode lets you set specific rules for every file type, from copy and update to skip or delete.
Before any sync kicks off, it runs a full side-by-side folder comparison first. You can pick how it matches files: quick checks by size and modification date, or full binary scans for total accuracy. Results are color-coded so you can tell at a glance what’s only on one side, conflicting, or identical. One really underrated detail is that it spots moved or renamed files by content, not just file name, so you don’t end up with duplicate copies just because you reorganized a folder. You can also filter files by name, extension, or path to cut out stuff you don’t need synced.
There’s solid advanced functionality under the hood too. On Windows, it uses Volume Shadow Copy to pull locked, in-use files without throwing errors. It works with Google Drive, FTP, SFTP, WebDAV and MTP devices, so it covers cloud storage and portable gadgets too. You can save jobs as batch tasks to run on a schedule, or use the bundled RealTimeSync tool to monitor folders in the background and sync changes automatically as they happen. The optional donation version adds email alerts, but the free build has everything most users will ever need.
