M&A migrations keep surfacing the same pattern: the mailbox move is rarely the...

M&A migrations keep surfacing the same pattern: the mailbox move is rarely the bottleneck. The real work sits in directory sync, app dependencies, and the sequencing of identity cutovers across the two environments. Tools that promise full automation for these scenarios are useful, but they still require careful mapping of source and target objects upfront. Without that step, permissions and access patterns break even when the data transfer succeeds. We have seen teams lean on a mix of migration platforms for the data side while handling coexistence and re-permissioning through established AD processes. That split approach keeps the cutover windows shorter and reduces the blast radius when something unexpected appears in the pilot wave. What part of an M&A migration has consistently taken longer than expected in the projects you have run?