Microsoft 365 alternatives for UK businesses

A Microsoft 365 alternative for a UK business is rarely one product. Microsoft 365 covers mail, chat, calls, files, documents and sign-in, usually on Windows desktops, and each of those has an open-source or independent replacement that your company can own. Most businesses replace the pieces one at a time and keep the Microsoft pieces that still earn their place.

The difference is less about features than about who is in charge. With open-source systems on servers in your company's name, you decide where the data sits and when the software changes.

What replaces each piece

These are the usual choices, not a fixed list. The right answer depends on what your business does.

Desktop

Ubuntu is a Linux operating system published by Canonical. A new LTS (long-term support) release comes out every two years, and each one gets five years of standard security maintenance (Ubuntu release cycle). Each desk is set up for the job that person does, with the apps they need and nothing else. The guide to Linux desktops for business covers hardware, apps and support.

Mail and calendars

Mail can run on your own server or with a UK mail host, on an account in your company's name. It uses open standards: IMAP for mail, CalDAV for calendars and CardDAV for contacts. That means it works with desktop mail apps such as Thunderbird, with webmail, and with the mail apps already on your phones. Your existing mail moves across with its folders. If mail is the part you'd rather not touch yet, Exchange Online can stay while everything else moves.

Chat, calls and phones

Element is a chat app built on Matrix, an open network for secure, decentralised communication (matrix.org). It handles team chat, direct messages and calls, with end-to-end encryption, and it can run on a server in your company's name. 3CX looks after your phone numbers, calls and video meetings. 3CX is commercial software, not open source, and it runs on a Linux server.

Teams can stay for meetings with clients who use it. Microsoft no longer supports the Teams desktop app on Linux, but the Teams web app is supported in Edge, Chrome and Firefox (Microsoft Learn: the Teams client). If you only join meetings your clients organise, you can join from a browser as long as their organisation allows anonymous joining, which is Microsoft's default setting.

Files

Nextcloud gives you shared folders that sync to laptops and phones, with sharing links and version history (Nextcloud Files). It runs on a server you own, in your office or on UK hosting. Your files stay as ordinary files, so another provider or your own team can pick them up.

Documents

LibreOffice is a desktop office suite: Writer for documents, Calc for spreadsheets and Impress for presentations. It opens and saves Word, Excel and PowerPoint files, and its own format, OpenDocument, is an open standard. Collabora Online, which is based on LibreOffice, lets people edit the same document together in a browser.

LibreOffice's own help says that some layout features in complex Microsoft Office documents are handled differently, and that it can run only some Excel macros (LibreOffice Help). We check your important files for both before anything moves.

Sign-in

An open-source identity platform, such as Keycloak or authentik, gives everyone one sign-in across your apps, with MFA. Both use the open standards OpenID Connect and SAML, so apps that offer single sign-on can usually connect to them. New starters get their apps on day one. When someone leaves, switching off one account removes their access everywhere it is connected. If you keep Microsoft 365 for some things, Entra ID can work alongside it.

Device management

Updates, settings and apps are managed centrally, and each desk's setup is kept in writing so it can be rebuilt the same way. If you keep Microsoft 365, Intune can enrol Ubuntu LTS desktops for compliance checks and use Conditional Access to control access to Microsoft 365 web apps in Microsoft Edge (Microsoft Learn: Linux in Intune).

What is realistic to keep

Leaving Microsoft 365 doesn't have to be all or nothing. These are the pieces worth thinking about before you decide:

• Teams for client meetings. If your clients run their meetings on Teams, you can keep it for that, or join their meetings from a browser.
• Exchange Online. Mail is the change people notice most. Some businesses move desktops, files and chat first and leave mail where it is for now.
• A Windows machine for one app. Some accounts packages, CAD tools and industry software only run on Windows. A Windows machine, or a hosted app, can do that one job.
• Excel for heavy macros. Workbooks built on VBA macros, and Access databases, may need to stay on Windows until they are rebuilt.

We connect what you keep to the rest, starting with sign-in. Anything you keep that is a cloud service stays in your Cyber Essentials scope, because cloud services can't be excluded. The guide Can Linux desktops pass Cyber Essentials? explains how scope works.

How to choose

Start from what each team does all day, not from a product list. These questions settle most of the choices:

• Which of your business apps already run in a browser, and which only run on Windows?
• Which spreadsheets and documents use macros, and who depends on them?
• Who do you swap documents with, and in what format?
• Do your clients expect Teams, or just a meeting link?
• Should your servers sit in your office or on UK hosting?
• Who will patch, back up and support it all once it is running?

Then compare on more than features. Ask who owns the accounts, who holds the admin passwords, where the data sits, and who decides when the price or the software changes. With nomsp, the domain, servers, hosting accounts and passwords are in your company's name (see self-custody).

Linux still costs money to run. Someone has to build it, keep it patched and support your people. Compare the whole running cost, not just the licences.

What changes for staff

For people who spend the day in a browser, the change is smaller than it sounds. Web-based business apps and accounts packages work the same way on Linux. The visible changes are:

• a different login screen, app launcher and file manager;
• LibreOffice instead of Word, Excel and PowerPoint, with some menus in different places;
• Element for chat and 3CX for calls, unless Teams stays;
• one sign-in, with MFA, for everything that supports it.

Each desk only has the apps that person needs, so there is less to learn. One team moves first and does its real work on the new setup before anyone else changes. Short training sessions cover the differences, and questions go to our support desk.

To see how this would work for your business, book a planning call. We'll go through what you use, what you'd like to leave and what has to stay. The full list of choices is on the stack page, and how to leave Microsoft 365 covers the move itself.

Common questions