---
id: data-transfers.first-run-for-this-pair-option
url: https://storagestudio.us/faq/data-transfers/first-run-for-this-pair-option
category: "Data Transfers"
subcategory: "Copy, Move and Sync"
question: "What does the “First run for this pair” option do in a two-way sync?"
alt_questions:
  - "first run for this pair checkbox"
  - "Should I tick first run for bidirectional sync?"
  - "two-way sync baseline option"
  - "bidirectional sync first time setup"
  - "resync option storage studio"
  - "why does two-way sync need a first run"
short_answer: "It establishes the starting point for a brand-new two-way sync. Tick it only on the first run for a pair of folders; using it again can overwrite one side with the other. Scheduled runs never use it."
tags: ["two-way sync", "first run", "advanced options"]
related: ["https://storagestudio.us/faq/data-transfers/what-is-bidirectional-sync", "https://storagestudio.us/faq/data-transfers/advanced-options-explained"]
applies_to: "all"
last_reviewed: 2026-10-01
---

# What does the “First run for this pair” option do in a two-way sync?

It sets the starting point for a new **Bidirectional sync**. A two-way sync works by comparing each side with how things looked last time; on the very first run there is no "last time", so this option tells it to establish one.

Tick it only once — the first time you sync a particular pair of folders. After that first successful run, leave it off. Ticking it again on a pair that's already set up can overwrite one side with the other.

You'll find it under **Advanced options** in **New Transfer**, and it appears only when Bidirectional sync is selected. Scheduled runs never use it, even if you ticked it on the original transfer.

Related: [What is Bidirectional sync?](https://storagestudio.us/faq/data-transfers/what-is-bidirectional-sync)