System migration: once, and done right

As a rule, not at all. Because we switch over in parallel operation, the old system keeps running while the new one takes over. There are short windows for individual steps – switching the mail flow, for example – usually outside business hours and lasting minutes.

Physically moving hardware is a different matter. For that we plan a weekend and keep a fallback ready in case of emergency.

Since 14 October 2025 it no longer receives security updates. An Exchange server without updates is reachable from the internet and therefore a favoured target – this is not a theoretical risk.

There are three options: move the mailboxes to Microsoft 365, switch to Exchange Server Subscription Edition, or run a hybrid setup. Which one fits depends on whether devices and applications on your premises still send mail via Exchange, and whether the data is allowed to leave the building. We clarify this in the assessment.

Step by step is almost always the better route, and for mailboxes and files it is technically built in. Some users are already working in the new system while the rest are still in the old one – and both groups can see each other.

With databases and line-of-business applications this is less often possible; there is usually a real cutover point. That is exactly why it gets rehearsed.

Initially it stays where it is. After the changeover the old system is switched off but not deleted straight away – usually it is kept for several weeks, often longer if retention periods apply.

In addition, every migration starts with a full backup whose restore we test beforehand. A backup you cannot rely on in an emergency is particularly expensive in a migration project.

That depends on the number of mailboxes or workstations, the number and condition of the servers, the line-of-business applications involved, and how well the existing environment is documented. That last point regularly makes the biggest difference.

We quote a fixed price for the assessment and then a reliable estimate for the implementation. After the assessment you can stop without any obligation and take the results with you.

Yes, and it happens more often than you might think – usually when a project has stalled halfway: half in the cloud, half on premises, and nobody dares to go further.

Even then, we start with an assessment. Taking over a half-finished state without having understood it regularly goes wrong.

We count completed migration projects since the company was founded in 1992, not individual mailboxes or computers. A project can be the replacement of a single server or the changeover of several sites with hundreds of workstations.

Over 34 years, that is roughly three to four projects a month. By far the largest share are Windows Server replacements and Exchange migrations – the two tasks that come up again and again in small and medium-sized businesses.

Not as a blanket promise – and anyone who makes one has not looked at your environment. How much downtime there is depends on the volume of data, the line-of-business applications and whether parallel operation is technically possible.

What we do promise: before the changeover, you will know what interruption to expect, when it will happen and what the way back looks like. In many cases the interruption can be limited to a weekend or a few hours – but that is the result of planning, not a promise made in advance.