Data Transfers · Copy, Move and Sync
Does Sync (one-way) delete files at the destination?
Short answer: Yes. Sync (one-way) makes the destination an exact mirror, so files there that aren't in the source are deleted. The source is never changed. Use a dry run first, or choose Copy if you only want to add files.
Yes — that's what makes it a mirror. After a Sync (one-way), the destination matches the source exactly, so any file in the destination that isn't in the source is deleted, and changed files are replaced with the source's version. The source itself is never changed.
That's ideal for keeping an up-to-date copy of a folder, but risky if the destination holds files you put there separately. Before the first run:
- Point the destination at a folder used only for this sync.
- Turn on Dry run (preview only) and start it.
- Read the log to see what would be added, replaced and removed.
- Run it for real when the preview looks right.
If you only want to add files without removing anything, choose Copy instead.
Related: What is a dry run?