The migration tool finished without errors. The dashboard is green. Then Monday hits and the help desk phone starts ringing.

Seven things break almost every time.

Shared mailboxes and delegated permissions don’t carry over cleanly. At one company, remediating these across six counties was its own workstream — scoped separately after cutover because nobody had mapped them beforehand.

Autodiscover and Outlook profile reconfiguration only surface after DNS cutover. The remediation window is short and the user impact is immediate.

Executives notice calendar and contact gaps first. BitTitan migrates these objects, but not always in the form users expect. That delta lands on the help desk fast.

Mobile devices need re-enrollment. Users don’t know this is coming unless someone told them before cutover. Most find out when their phone stops syncing.

Mail flow breaks quietly. Connector misconfigurations and DNS propagation delays don’t announce themselves. They show up as missing messages hours later.

Licensing gaps look like migration failures. Users who cut over before their M365 license is assigned hit access errors that look like tool problems. They aren’t. Pre-assign before the batch runs.

Hyper Care gets closed too early. On one project supporting 500+ users across three post-migration periods, the window caught failures the dashboard never flagged. Issues were still surfacing days after cutover. Closing Hyper Care on schedule without checking ticket volume first is how small problems become executive calls.

A green dashboard on cutover night means the tool finished. It doesn’t mean the migration worked.

#ExchangeOnline #EmailMigration #M365