"It should all be there" is not the same as knowing it is. Verification lists every source folder, calendar and drive again and checks each item against the target. Retries take care of the items that failed on the way.
Verification
- Press Verify everyoneOn the Migration tab. It runs in the background, one user at a time, read-only on both tenants.
- Read the cardPer user: source items, in target, missing, checked. Open Details for every container — each mail folder, contact folder, calendar and the drive.
- Copy missing itemsIf anything is listed, press Copy N missing items. They are queued and copied; verify again to confirm.
"In target" is what the target reports. It can be higher than "source items" if the target already had content, and lower if the source received new mail since the last pass — that is what delta passes are for. "Missing" is the number that matters: source items MigrateX never copied, or files changed since they were copied.
Retries
An item that fails during a pass — a locked file, a busy mailbox, an oversized message — is remembered with its reason. Retry N failed items tries each again, up to five times, and keeps the newest reason. Recovered items count as migrated. Sites and Teams have the same button on their tab.
Resync
Every user on the Migration tab has a Resync button: it runs a delta pass for that one person, copying only what changed since their last pass. The menu next to it offers Full re-check, which reads the whole source again — every folder and file — and copies only what is missing or changed; use it when you suspect something was skipped. Resync everyone and Full re-check for everyone are at the bottom of the list. A user who is already syncing is left alone.
Nothing arrives twice
Every pass, delta pass, retry and "copy what is missing" checks its ledger first, so an item that already crossed is skipped. For the one case a ledger cannot see — the platform accepted an item but the answer was lost on the way back — MigrateX asks the target before creating again: mail by its Message-ID, contacts and events by a stamp MigrateX writes on each one, files by their path, chat messages by their original time and author. Running a migration again, or resyncing before cutover, never produces duplicates.
Notes that aren't failures
Some things can't move and are listed so nobody forgets them: OneNote notebooks, sharing links, people who aren't matched, private channels, custom lists. They are not retried; they appear in the report.