Structured implementation of cloud exit from Microsoft 365

This article is a continuation of the article "Successful cloud exit strategy". It shows in a practical way how companies can leave Microsoft 365 in an orderly manner, remain capable of acting and gain time to make informed decisions about cloud, hybrid or on-premises.

The linked article focused on the question of why an exit strategy from cloud services makes sense and what the basic principles are. This article takes the idea further and describes the orderly withdrawal from Microsoft 365 to an already connected, dedicated environment in the data center.

The aim is not to exit the cloud, but to be able to act: to work quickly and stably in case of doubt, to gain time and to decide without pressure what the digital workplace should look like in the future - whether again in the cloud, in a mixed variant (hybrid) or permanently in your own infrastructure (on-premises).

Many organizations already operate Microsoft 365 in conjunction with their own directory service. Users and groups are synchronized between local login and Microsoft Entra ID (formerly Azure Active Directory, Azure AD). Email is also often organized as a combined operation (Exchange Hybrid), with content stored partly in SharePoint Online and partly locally.

It is precisely this network that can serve as a safety net in the event of a cloud exit: Identities, groups and authorizations do not have to be reinvented; logins and rights remain traceable; transitions can be controlled in a targeted manner.

A clearly defined minimum goal is important: the smallest meaningful set of functionalities ("Minimal Viable Workplace"). What needs to work smoothly in the first few days - login, e-mail, access to important files, simple collaboration? Which convenience functions can be added later? The more precise this picture is, the more structured the move back will be - and the more time you will have to make a fundamental decision about the way forward.

The first step is to define the authoritative data source (source of authority) for user accounts. Keep synchronization stable, reduce unnecessary dependencies on cloud services and simplify login paths. Every superfluous asset costs valuable time in the cloud exit.

Email remains an essential part of the communication infrastructure. An orderly withdrawal from Exchange Online is possible if mailboxes, including authorizations and archive mailboxes, are taken over completely, the delivery routes are switched to the local environment in good time and the entries for mail delivery (MX records) are converted at the appropriate time. A short transition phase with shared operation can help, but should be clearly limited in time so that no duplicate statuses arise.

For OneDrive repositories, SharePoint areas and the documents in Teams channels, it is advisable to proceed in waves: First the active areas with a high change rate, later legacy data, which can also be available as a readable archive during a transition period.

The biggest challenge is short communication with chat, channels and meetings, as there is no fully-fledged local replacement for Microsoft Teams. A pragmatic approach has proven its worth: Past content is archived in a legally compliant manner and made retrievable; ongoing communication is organized on a locally operable solution.

This is where Skype for Business Server (Skype SE) comes into play.

Skype SE can serve as a local communication and telephony anchor—either permanently or for a transitional period. A particularly valuable feature is that Skype SE can run in mixed operation with Teams (hybrid/convergence): To do this, a link is established between the local Skype environment and Microsoft 365, typically via a shared address space for chat and telephony (shared SIP address space) and edge services for connections to other networks (edge federation). This allows chat, calls, and presence to be coordinated between the two worlds, while you set the pace yourself. For telephony, the existing infrastructure can remain connected via direct routing.

Retreating to your own environment is feasible, but not without cutbacks. Some cloud-specific functions are not available locally or are only available to a limited extent. These include in particular:

• Task and planning services such as Planner and To Do
  Return often only as file export; rebuilding in other tools required
• Automation and low-code processes
  Power Automate and Power Apps cannot be replaced 1:1
• Real-time collaboration
  Collaborative editing with the familiar depth and speed
• Cross-service search
  Microsoft Search across all content
• Additional collaborative functions
  Whiteboard, loop components

This clarity is not a disadvantage - it prevents surprises later on. Where functions are missing, transitional solutions can often be defined: archived content can be made available on a read-only basis, task lists can be managed in other systems, workflows can be remapped in a simplified manner or search requirements can be focused on clearly defined data areas.

The decisive factor is to openly name, prioritize and actively control these restrictions - not to let them run "on the side".

Not everything has to be perfect on the first day. The key is to consciously prioritize the data paths.

• Critical areas - such as ongoing projects, customer files or central specialist mailboxes - should be immediately available in full and writable.
• Less active areas can initially be provided as a readable archive, with a clear plan for later transfer.
• Old data is sorted according to quality, relevance and usefulness and migrated or archived in a targeted manner.

Short, clearly defined delta windows between test and production migration help to make final changes and ensure data consistency.

During cloud exit, there must be no phase in which organization and communication stand still. The designated survivor principle describes a clearly defined core operation that functions independently of Microsoft 365 - even if migrations are delayed or individual services are not yet available.

This core operation includes:

• At least one functional, independent communication system (mail, chat, telephony) outside of M365.
• Mirrored administrator access for emergency and partial failure operation.
• Prioritized migration of the most important user groups
• Provision of further jobs in planned waves.
• Critical information (e.g. manuals, emergency plans, organizational overviews, contact directories) available locally and autonomously in advance
• Clearly defined core operation that also works with delays

This concept prevents an exit from leading to operational paralysis

With the cloud exit, responsibility for end devices, access and security shifts completely back to the organization's own environment. Protection mechanisms that were previously implicit in cloud operation must now be explicitly planned, prioritized and operated in order to ensure the organization's ability to work

The first bottleneck is the end devices. In Microsoft 365, they are typically managed via Intune. Upon exit, they must be transferred to a new on-premises management environment—a process that takes time and requires clearly defined procedures. To ease the transition phase, virtual desktops offer immediately usable work environments. For administrators and particularly critical roles, physical replacement devices that function independently of Intune should also be available.

Parallel to this, employee access is again predominantly shifting to the data center. Sufficient network resources, low latency and clean security architectures are therefore crucial. Access can be via VPN, reverse proxy, zero-trust solutions or mixed approaches - depending on the security requirements and initial situation.

Publicly accessible services such as webmail or SharePoint need to be hardened again. This includes multi-factor authentication (MFA), web application firewalls (WAF) and clearly demarcated DMZ structures.

All in all, going back to the data center requires both rebuilt device management and a robust network and security design to keep the organization operational during and after the exit.

Not every theoretical Microsoft 365 outage should be treated equally. The type and duration determine whether a failover makes sense - and how much time and room for maneuver can be gained. Four typical situations provide guidance:

1. Announced outage.

   There is advance warning time. The transition can be planned: Pilot groups are brought forward, an orderly parallel operation is set up, email channels (MX) are prepared and files are transferred in stages. Meetings and telephony can be moved to Skype SE as planned, while Teams continues to run in parallel.
   Advantage: little disruption, lots of transparency.

2. Sudden failure.

   No advance warning. The aim is stable emergency operation: local login immediately, receive and send e-mail locally as quickly as possible (DNS adjustment), provide critical files from the last backup. Short communication is stabilized via Skype SE; only use Teams if available.

   It is crucial to strictly prioritize the groups of people.

3. Short-term outage (hours to a maximum of three days).

   The first thing to consider here is whether a failover makes sense at all. As migration takes time and the way back is generally difficult, it may be better to consciously tolerate such a failure.

4. Long-term outage (days to weeks).

   What counts now is the complete return. Identities are defined locally as leading, MX records are permanently converted, mailboxes are operated productively locally and files are transferred comprehensively with metadata and versions, collaboration takes place via Skype SE (or an alternative platform) as the core. The migration of the workforce takes place in waves; accompanied by regular, legally compliant external communication.

One aspect that is underestimated in many exit scenarios is the enormous amount of time required for data migration. A cloud exit doesn't just mean copying individual files, but the structured reconstruction of the information landscape.

Typical migration paths are:

Exchange Online → Exchange On-Prem

Mailboxes, folder structures, rules, permissions and archives must be completely transferred. A complete retraction is usually only possible via backup and restore mechanisms, which are functionally reliable but poorly scalable. Large mailboxes often require hours to days per mailbox.

SharePoint Online → SharePoint On-Prem

Although both platforms appear similar, they are not identical. Versions, list structures, authorizations and web parts must be retained; a pure file copy is out of the question. Depending on the scope, the way back to the local SharePoint farm can take several weeks.

Teams data & OneDrive repositories → Fileshares / SharePoint On-Prem

Teams technically store files in SharePoint, but chats, Planner data, wikis and channel configurations need to be considered separately. OneDrive data, on the other hand, often ends up in classic file server structures that need to be prepared in advance.

The time factor is therefore not a technical detail, but a central lever for functioning business continuity. Those who plan for it realistically gain room for maneuver - those who underestimate it come under pressure.

Technology can be migrated; habits need guidance. Communicate openly about what is changing, when, where help can be found, and what the minimum functionality will be in the first few days. Short instructions with pictures (“Login,” “Email on the go,” “Where can I find my project data?”) often have a greater impact than long circular emails. Appoint contact persons in the teams who are available to provide initial assistance, and celebrate visible milestones—this creates trust.

A cloud exit from Microsoft 365 to your own environment provides a deliberate breathing space. Operations are shifted to a terrain that is fully controllable - not as an end in itself, but to gain time and room for maneuver.

Whoever stabilizes logins and rights first, transfers emails and central content with content fidelity and pragmatically reorganizes collaboration - for example with Skype SE as a bridge in mixed operation with teams - gains exactly what counts in an emergency: Time, overview and scope for decision-making.

Yes, some cloud functions are missing or only available to a limited extent. But with a clear prioritization of the affected groups of people, clear transition rules and an honest look at must and can issues, the company remains capable of acting - and can decide without operational pressure whether the next step is back to the cloud, a hybrid setup or a strengthened, in-house IT.

The best exit strategy is the one you never need. When it comes down to it, it protects business operations, data and entrepreneurial freedom of choice.