The assessment reads both tenants, pairs people up and tells you whether the move is ready — and if not, exactly what to fix and where. It is read-only and free; run it as often as you like.
The score
- 85 – 100 — Ready to migrate. Review the matched users and start a pilot.
- 50 – 84 — Ready, with things to tidy up. You can start a pilot; sort the warnings before the full wave.
- Below 50 — Not ready yet. One or more blockers. Fix them, then run again.
Blockers pull the score under 50 no matter what. Each warning costs 12 points. Notes don't change the score; they describe what the move will look like.
The findings, and where they are fixed
| Finding | Level | What to do |
|---|---|---|
| No users found in the source | Blocker | Permissions are still propagating. Wait a few minutes, run again. |
| N users have no account in the target | Warning | Create the accounts in the target and run Auto-match; or pair by hand or exclude on Users. |
| Matched target account has no license / mailbox | Warning | Assign a license in the target (or turn Gmail on), wait for the mailbox, run again. |
| Not enough MigrateX licenses | Warning | Order more under Licenses, or migrate in waves. |
| Usage reports are anonymised | Warning | Microsoft 365 admin center → Settings → Org settings → Reports → turn off concealed names. |
| Mailboxes larger than 50 GB | Note | Start them in the first wave; they take longest. |
| Shared mailboxes, groups, sites, Teams found | Note | Migrate them from their own tabs once their people are matched. |
| Guest accounts | Note | Guests belong to other organisations; re-invite them after cutover. |
What's in the source tenant
Below the verdict the page lists what was found: people, mail size and item count, drive size, shared mailboxes and groups, sites, Teams and domains. Use it to sanity-check the scope and to size the waves.
Run it once more right before cutover.It will show anyone added to the source since, and whether every matched account is ready.