Mail migration without service loss or interruption

A messaging migration involves transferring all e-mail, contacts, calendars, rules and permissions from one platform to another. It modernizes the collaborative environment, improves security and availability, and reduces maintenance costs. It also offers the possibility of integrating new tools such as Teams, OneDrive or Google Drive, for more fluid, centralized communication.

We master migrations to and from Exchange on-premise, Exchange Online, Google Workspace, Lotus Notes, Zimbra, MDAEMON, OVH and all IMAP/POP-compatible systems. We also manage hybrid environments and multi-domain consolidations. Each project is tailored to your technical constraints and network architecture.

The duration depends on the number of users, the volume of data and the method chosen. An SME with 100 boxes can be migrated in a few days, while a multi-site group may require several weeks. Progressive migrations enable the switchover to be planned over several phases, limiting interruptions.

Big Bang migration involves a complete switchover in a single operation: users leave the old system and immediately start working on the new one. It's a fast method, suitable for homogeneous environments. Synchronized progressive migration, on the other hand, enables temporary cohabitation between the two platforms, with automatic synchronization of messages and calendars. This reduces risks, especially for large accounts.

Yes, IT Systèmes guarantees full recovery of mailbox history, including old e-mails, PST/OST archives, recurring calendars, contacts, signatures and personalized rules. Our automated checks ensure completeness and consistency after switchover.

We apply TLS/SSL encryption protocols, OAuth authentication, and full backups before, during and after migration. Audit logs and compliance reports are produced. In the event of an incident, a full recovery plan is activated. This approach guarantees data confidentiality and integrity.

In most cases, no. Thanks to our phased approach and automated synchronization, users can continue to send and receive e-mail throughout the migration, without any noticeable interruption. For migrations in Big Bang mode, a short interruption may be necessary at the time of the final switchover, but this is planned for non-working hours (NOW), evenings, nights or weekends, so as not to impact production. This organization guarantees continuity of service and peace of mind for users.

We migrate local and server archives, PST/OST files and shared boxes, while preserving permissions and folder structures. Retention and archiving policies are applied automatically, guaranteeing faithful and compliant recovery.

Yes, IT Systèmes manages multi-domain and multi-tenant migrations, for example during mergers or acquisitions. We synchronize data between Microsoft 365 tenants or separate domains, ensuring a smooth and seamless integration.

We prepare internal communications, user guides and online or on-site training. Pilot users participate in testing, and dedicated technical support remains available after the switchover. This reduces resistance to change and promotes rapid adoption of the new system.

We have already migrated environments exceeding several tens of terabytes and over a million mailboxes. Our tools parallelize workflows and optimize transfers, guaranteeing fast processing times even on international projects.

Because we combine experience, tools and methods. With over 2 million boxes migrated and expertise in the most demanding environments, we guarantee secure, compliant and seamless migrations. Our tools enable us to synchronize huge volumes of data seamlessly, and our human support ensures smooth adoption of the new environments.