Migration complete. Status green. The real work starts now.

Most teams aren’t watching the right things in the first 72 hours.

Client connectivity first. Check desktop, mobile, web, and Exchange Online. Legacy Outlook profiles and mobile enrollment are where the first failures show up — every time.

Test inbound and outbound mail routing. New DNS records don’t always behave cleanly on cutover. Messages sitting in legacy connectors and silent rejections won’t announce themselves. You have to go looking.

Spot-check shared mailboxes immediately. Migration tools don’t always transfer them cleanly. The users who notice are not the patient ones.

Confirm OneDrive and SharePoint access. Check site permissions for every migrated user. ShareGate migrations with custom permission levels need manual validation — assume it’s required until you’ve confirmed otherwise.

Verify Teams. Users need to see their channels, access content, and reach SharePoint-backed files inside Teams. These dependencies break in sequence, so check them in sequence.

Watch help desk volume. Ticket patterns tell you whether a problem is isolated or systemic. On one project we tracked escalations across 500+ users during Hyper Care to separate remediable exceptions from signals that needed a broader fix. The pattern showed up in the queue before anyone escalated it verbally.

Cutover means the migration finished. Hyper Care is how you find out if it worked.

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