Preview a sync before going live

Turning a sync on for the first time — pointing it at your live Google Workspace — is the scariest moment in setup. Preview mode removes the fear: the sync is on, it runs its real logic against your real data, but instead of making changes it records what it would do. You explore the plan, and when you're confident, flip to live — and the next run applies exactly what you previewed.

The three states

A sync is always in exactly one state, shown plainly in Sync services:

Disabled — the service doesn't run at all.
On — preview only — the sync runs and plans, but nothing is changed in Google. While previewing, only the user sync is planned; groups, Classroom and memberships are held entirely.
Enabled — live — the sync applies its changes as normal.

Steps

Step 1 — Turn Google sync on in preview {#step-1}

Go to Settings → Sync services, switch Google Workspace on, and choose Preview — plan only as the mode. The badge changes to On — preview only (no changes applied) so the state is unmistakable.

Step 2 — Run a preview {#step-2}

Open Sync preview (linked from the mode setting, or /v2/admin/sync/preview) and select Run preview now. The sync runs in the background — usually a few minutes — computing its plan the same way a live run would, including reading your real Google directory.

Step 3 — Explore the plan {#step-3}

The plan appears as drillable categories — accounts to create, accounts to update, accounts to suspend, org units to ensure, Classroom ownership moves — each expandable to the specific people and details ("Create Google account [email protected] in OU /Learners"). Every row links to the user so you can check anything that looks surprising.

Sync preview showing expandable categories of accounts to create, update or suspend with example rows

Step 4 — Flip to live {#step-4}

Happy with the plan? Back in Sync services, switch the mode to Live — apply changes. The next sync run applies its changes for real. Because the preview was computed by the same code that performs the live sync, what you saw is what happens.

Honesty notes

Preview mode never writes to Google — account changes, org units and Classroom transfers are all held and recorded instead.
The plan reflects the moment it was generated; each preview run replaces the previous plan. If your MIS data changes, run a fresh preview.
Preview currently covers the user sync (the create/update/suspend decisions). Groups, Classroom and membership syncs don't run at all while previewing — they'll be added to the plan in a later update.

Troubleshooting

"The plan is empty" — run a preview first (Step 2), and check the school actually has Google sync configured (domain set). If everyone is already in sync, an empty plan is the correct answer.
"I flipped to live but nothing happened yet" — live changes apply on the next sync run (scheduled, or trigger one from the Sync dashboard).