Every business on Microsoft 365 has had this argument. Somebody cannot find a document, somebody else says it is in Teams, a third person says Teams is not a place files go and the file turns out to be in a chat message from four months ago.
There is a rule that settles it, and it has become worth applying properly now that AI tools answer questions from whatever they find.
The rule
Ask who owns the file, not who is working on it.
- OneDrive — the file belongs to you. Drafts, working notes, your own copy of something, anything the business would not miss if you left.
- SharePoint — the file belongs to the business. Contracts, policies, project documents, client files, anything somebody else would need on Monday if you were unavailable.
- Teams — not a storage location. It is a way of working with files that live in SharePoint.
That third point causes most of the confusion, so it is worth stating precisely.
Teams is a window, not a cupboard
When you post a file in a Teams channel, it is stored in the SharePoint site belonging to that team. Teams is showing you a view of SharePoint. Nothing is stored "in Teams".
The exception is the one that causes trouble. Files sent in a private chat are stored in the sender's OneDrive and shared with the recipients. Which means:
- They are owned by an individual, not the business.
- They are invisible to anyone not in that chat, including their manager.
- They are subject to OneDrive deletion when that person leaves.
The tender response that only exists as an attachment in a chat between two people who have both since left is not a hypothetical. It happens constantly.
If a file matters and it arrived in a chat, move it to the team's SharePoint site the same day. That single habit prevents most Microsoft 365 file loss.
Why this matters more now
For years, poor file organisation was an inconvenience. People asked a colleague and moved on.
Two things changed. Search in Microsoft 365 became good enough that people stopped browsing and started searching, which rewards clear names and punishes duplicates. And Copilot began answering questions from the file estate, with total confidence, from whatever version it happened to find.
A business with six copies of the price list now has a tool that will quote one of them to a customer. That has moved file hygiene from tidiness to a readiness question.
How to structure SharePoint
Three principles, and the first one is the one businesses get wrong.
Structure around work, not around the org chart
Departmental sites feel logical and fail in practice, because most real work crosses departments. A project involving sales, operations and finance has no natural home in a departmental structure, so it ends up in whichever site the loudest person prefers.
Sites for the things the business does — projects, clients, product lines, functions with genuinely private content such as HR — work better.
Keep it flat
Many sites with shallow folder structures beats a few sites with deep nesting. Search does the finding. Folders exist to group things a person will genuinely browse, which is rarely more than two levels deep.
If you are migrating a shared drive, resist the temptation to lift the structure across intact. Fifteen years of nesting made sense to whoever built it in 2011 and to nobody since.
Name files so they can be found without the folder
Because search results do not show the folder path prominently. Ashcombe-Joinery-Quote-2026-04.docx is findable. Quote v3 FINAL.docx is one of forty identical results.
Fixing an estate that has already sprawled
Do not attempt to reorganise everything. It never finishes and it makes people hate the project.
- Identify the answer set. The twenty to thirty documents that answer the questions people actually ask. Current price list, standard terms, live policies, key templates.
- Put those in one obvious place with clear names.
- Archive what they superseded. Move it out of the working area rather than deleting it — this argues with nobody and removes the duplicates from search.
- Move business-critical files out of personal OneDrive. Run a report on what departed staff still own.
- Leave the rest alone. The archive can stay messy. It is not the thing causing the problem.
That is two or three days of work for most small businesses, and it fixes the visible symptom completely.
The habit that keeps it fixed
One rule, stated in induction and repeated occasionally: if it matters, it goes in the team site, not in your OneDrive and not in a chat.
Everything else is enforcement, and enforcement is much easier when the structure makes the right thing the easy thing.
If you would like a hand designing the structure, running the migration and putting the retention and sharing controls behind it, that is standard work for our managed IT team, and it is usually the highest-value week you can spend in Microsoft 365. Get in touch.
