Ironstack
REPLACE · MICROSOFT 365
OneDrive, SharePoint and Office have owned equivalents: Nextcloud with Collabora or OnlyOffice on a server that is yours, and Exchange replaced by an EU mail provider on your own domain. Here is the honest version of what that swap involves.
I · WHAT MICROSOFT 365 ACTUALLY COSTS
Microsoft 365 Business Standard runs at roughly €12.50 per user per month on the annual plan as of early 2026; Business Premium, which many companies get pushed toward for security features, is around €22. On top of the base tiers sits the perpetual upsell, currently wearing the name Copilot, at a price per seat that can exceed the plan it is bolted onto. The numbers below are the conservative published tiers.
Business Standard · ≈ €12.50 per user per month · as of 2026
Before the Copilot upsell · rising with every renewal
And as with Google, the invoice is only half the price. Your documents, mail and internal conversations sit in an American cloud under American jurisdiction, and every renewal is an opportunity for the terms to shift under you.
II · THE OWNED EQUIVALENT
The replacement is three pieces. Nextcloud on a server you own covers OneDrive and SharePoint: files, sync, sharing, calendars and contacts. An open office suite, Collabora or OnlyOffice, runs inside it for collaborative documents; OnlyOffice has the best .docx and .xlsx fidelity of the open suites, which matters when your history is twenty years of Word files. Exchange is replaced by a specialized EU mail provider on your own domain.
The email sentence again, because it applies here too: self-hosted email deliverability is hard, and I recommend a dedicated EU provider rather than running your own mail server. You get EU jurisdiction and portability without gambling your invoices’ inbox placement. If you insist on fully self-hosted mail, I will build it, with the trade-off in writing first.
III · WHAT THE MOVE INVOLVES
The migration runs through the five-phase method: four to eight weeks from audit to handover for a typical small company, with the exact timeline fixed in the audit before you commit to anything.
Microsoft 365 keeps running untouched while the new environment is built next to it. Files move from OneDrive and SharePoint with their structure and sharing deliberately rebuilt rather than blindly copied; mail history migrates over IMAP; calendars and contacts are exported and verified. Documents that matter get opened and checked in the new suite during validation, before the switch. The switch itself is a DNS change and a final sync in a window you approve, with a tested rollback.
The realistic risks: the two Excel power users nobody mentioned at kickoff, SharePoint automations that only surface when they stop firing, and old shared mailboxes with unclear ownership. This is precisely why the audit comes first, and why validation is a phase rather than a hope.
A Microsoft 365 exit is €1,250 to €2,500, excl. btw, priced per audit.
Indicative, not a calculator: the audit tells you exactly where you land, in writing, before anything is signed.
See the full price register for how a Workspace Exit compares with everything else.
IV · WHERE YOUR DATA ENDS UP
After the move, your files and calendars live on a server you own, in an EU data center, under EU jurisdiction, under your accounts. Your mail lives at an EU provider under a GDPR processor agreement, on your own domain. No American cloud provider in the chain means no CLOUD Act ambiguity, and your GDPR processor register gets shorter instead of longer.
The exit clause applies from day one: server, accounts and documentation are yours, so whether you later leave Microsoft, or me, you take everything with you.
Most companies can; some people in them cannot, and the audit finds out which is which. OnlyOffice has the best .docx and .xlsx fidelity of the open suites and covers everyday documents and spreadsheets well. Heavy Excel work with macros and Power Query is the honest exception: for those two finance seats, keeping a desktop Office license alongside the owned stack is a perfectly sane outcome.
Email goes to a specialized EU mail provider on your own domain, because self-hosted email deliverability is a risk I recommend against; calendars and contacts live in Nextcloud and sync to phones and mail clients over open standards. Your addresses do not change, and your history migrates over IMAP.
Nextcloud Talk covers chat and video calls for internal use. Honestly: it is not Teams at enterprise scale, and if your clients live in Teams meetings you can keep joining those from a browser without paying for the whole suite. Chat with real self-hosted depth would be a separate tool, which the audit can scope.
The files themselves move cleanly to Nextcloud with structure and sharing rebuilt deliberately. What takes real planning is everything bolted onto SharePoint over the years: Power Automate flows, embedded lists, forms. The audit maps exactly that before anything is promised, so the proposal is grounded in your environment, not a template.
A typical small-business migration runs four to eight weeks from audit to handover. Microsoft 365 keeps running untouched until the deliberate switch, in a window you approve, with a tested rollback.
The running costs stop scaling per seat: a server plus EU mailboxes typically undercuts a 10-seat Business Standard subscription, and the gap widens with every hire and every Copilot-style upsell you skip. The move itself is a Workspace Exit at €1,250 to €2,500, excl. btw, priced per audit, so think payback over a year or two, not overnight savings.
The audit maps what your team actually uses inside Microsoft 365, what it costs per year, and which seats genuinely need to keep Office, for €850 fixed, excl. btw, fully credited against a migration signed within 60 days, with a written report that is yours whatever you decide.