It’s the question that comes up the moment a business owner starts adding up subscription fees and thinking about data ownership:
“Could we just leave Microsoft 365 entirely? Run our own stuff, own our data, stop paying per-person every month forever?”
The honest answer is: partly, and it depends. Some of Microsoft 365 has excellent open-source, self-hostable replacements. One piece of it is genuinely hard to leave well. The businesses that get this right know the difference going in — so let’s go feature by feature, honestly.
What Microsoft 365 actually bundles
“Microsoft 365” isn’t one thing. It’s a bundle, and you have to evaluate the pieces separately:
- Email and calendar (Exchange Online + Outlook)
- File storage and sharing (OneDrive + SharePoint)
- Documents (Word, Excel, PowerPoint)
- Team chat and meetings (Teams)
- Identity and login (the account that ties it all together)
Leaving M365 means finding a home for each. Some moves are easy wins. One is a trap.
The easy wins: files and documents
File storage and sharing. This is the strongest case for self-hosting. Nextcloud (which we walked through in detail earlier in this series) replaces OneDrive and SharePoint comprehensively: desktop sync, mobile apps, sharing links, version history, the works — on a server you own, with your files in your building. For a business motivated by data sovereignty, moving files in-house is the highest-value, most achievable step.
Documents. LibreOffice is a mature, free office suite that reads and writes Word, Excel, and PowerPoint files. For the large majority of small-business documents, it’s a genuine drop-in replacement. The honest caveats: very complex Excel spreadsheets with heavy macros, or precise formatting handoffs with outside parties who use Microsoft, can hit friction. If your business lives and dies in advanced Excel, test thoroughly before you commit.
The doable middle: chat and meetings
Teams has self-hostable equivalents. Mattermost is an excellent open-source team-chat platform (a close Slack/Teams analog) you can run on your own server, keeping your internal conversations genuinely internal. For video meetings, Jitsi is a capable self-hosted option. These work well — the realistic catch is external meetings: if your clients all live in Teams or Zoom, you’ll likely keep one foot in those tools for outside calls even after moving internal chat in-house.
The trap: email
Here’s the piece we will tell you, plainly, not to self-host casually: email.
The mail server software is the easy part. The hard part is that the big providers — Microsoft, Google — are deeply skeptical of mail coming from small self-hosted servers. Without exactly the right setup, your legitimate business email lands in spam folders or is rejected outright, and you may not even know it’s happening. Deliverability, spam filtering, blacklist management, and the authentication records that make the big players trust you are a specialized, ongoing discipline.
This is such a common and costly mistake that we’re devoting an entire upcoming post to it. The short version: self-hosting email to own your data is a reasonable goal, but doing it so your mail actually arrives requires real expertise — which is exactly why our on-premise service includes a hybrid email approach that keeps your data accessible in-house while ensuring the big providers still accept your mail. Owning your email and having your email actually deliver are two different problems, and most DIY attempts solve only the first.
Identity: the quiet hard part
The least visible challenge is identity — the single login that currently ties all your Microsoft services together. Self-hosting your stack means standing up your own identity and access management so staff have one secure login across Nextcloud, chat, and the rest, with proper offboarding when someone leaves. It’s very doable, but it’s real work, and it’s the kind of foundational piece that’s miserable to retrofit later. Done right, it’s also a security upgrade; done as an afterthought, it’s a sprawl of separate passwords.
So, can you actually do it?
Here’s our honest verdict for a typical Houston small business:
- Files and documents: yes, and it’s the best place to start — high value, achievable, real ownership.
- Chat and internal meetings: yes, with the understanding that external calls may keep you on mainstream tools.
- Email: yes only with a hybrid, professionally-run approach — don’t naively self-host it.
- Identity: plan it deliberately from the start, not bolted on at the end.
For most businesses, “ditching Microsoft 365” in practice means a thoughtful hybrid: pull the high-value pieces in-house where ownership matters, run them properly, and keep the cloud where it’s genuinely the better tool. That’s not a failure to leave — it’s the smart version of leaving.
The realistic path
A migration like this is very doable, and it’s also exactly the kind of project where the difference between “we tried to leave M365” and “we successfully own our data now” is execution: a sane migration order, no data lost in the move, identity done right, and email that actually arrives.
That’s the work we do. We plan and run on-premise and open-source migrations for Houston small businesses — Nextcloud for files, open-source collaboration, hybrid email that delivers, and the identity layer underneath — sequenced so the business keeps running the whole time. It’s deliberate, professional work at professional rates, not a weekend swap.
If you’re seriously weighing a move off Microsoft 365 and want a straight assessment of which pieces are worth it for your business, book a free discovery call. We’ll tell you what to move, what to keep, and in what order.
Aspendora Technologies provides cybersecurity, managed IT, and expert on-premise & open-source solutions to Houston-area small businesses since 2010.