Three months after joining as SharePoint admin for a regional accounting group, Priya ran her first full site inventory. Of 140 SharePoint sites in the tenant, 38 had only a single owner, and six of those owners had already left the company. Six sites with no active owner, no one to approve access requests, and permissions frozen in place from a time nobody could now remember. It was a governance debt that had built quietly over years. Microsoft's new minimum site owner requirement is, among other things, an attempt to stop exactly that from happening.
What the SharePoint minimum site owner requirement actually says
Microsoft now requires every SharePoint Online site to have at least two owners. The requirement was announced via Microsoft 365 Message Centre notification MC1402118 and applies to all site types: team sites, communication sites, and Microsoft Teams-connected sites.
Sites with only one registered owner receive in-product notification prompts visible to that owner and to global administrators. Microsoft has signalled that enforcement will tighten over time. As of mid-2026, the main mechanism is notification rather than hard blocking, but that is expected to change as the rollout matures.
Why single-owner sites are a governance risk
The case against single-owner sites is not theoretical. It plays out the same way across organisations of every size.
When the sole owner leaves (resignation, redundancy, long-term leave), the site becomes effectively ungoverned. Access requests from new staff or external collaborators arrive but go unanswered because the owner's inbox is closed. Nobody else has the permission to add or remove members, modify library settings, or rename the site. IT must step in manually via the SharePoint admin centre to appoint a replacement owner, an intervention that often surfaces only after someone has already been blocked from something they needed.
There is also a subtler problem. A site with a single owner often has no succession plan for content governance. If the owner was the only person who knew the site's purpose, its retention requirements, or which content was still active, that institutional knowledge disappears with them. The two-owner rule does not solve that problem directly, but it creates a structural prompt to involve a second person who at minimum knows the site exists.
Finally, single-owner sites tend to accumulate unique permissions. The sole owner may have granted ad-hoc access over time without following any consistent policy. When someone eventually audits the site, they often find external guests with lingering access, broken permission inheritance on several libraries, and no clear record of why any of it was granted. With two owners, someone is far more likely to catch these patterns before they compound.
Finding SharePoint sites with only one owner in your tenant
There is no single-click report in the Microsoft 365 admin centre that shows "sites with exactly one owner." You have to construct it.
The most accessible route is the SharePoint admin centre under Sites > Active sites. The list includes a primary administrator column and an "Owners" column showing additional owners. Sites where only the primary administrator is listed have one owner. Export the list to CSV and filter in Excel on the owners column to isolate them.
PowerShell gives you more control. Get-SPOSite -Limit All returns all sites, and combining it with Get-SPOSiteGroup or Get-SPOUser allows you to filter by the site's Owners group membership count. The setup takes some scripting effort but produces a reliable, automatable export.
A faster alternative: Report Master exports site inventory data including ownership fields. You can pull a tenant-wide site list to Excel and filter for single-owner rows without writing any scripts. The guide to finding SharePoint sites without an owner covers both the admin centre and Report Master approaches step by step.
Remediating single-owner sites at scale
Once you have the list, remediation is straightforward for most sites: open the site settings, go to Site permissions, and add a second owner. The challenge is deciding who the second owner should be.
Some organisations use a tiered approach:
- Team or department sites: the relevant department head or their designated deputy becomes the second owner.
- Project sites: the project manager and the department manager share ownership; when the project closes, ownership transfers to the archive admin account before the site is decommissioned.
- Orphaned sites (where the original owner has left): IT takes temporary ownership to audit the site's purpose, then assigns a business owner or schedules the site for decommission if it is no longer needed.
For tenants with dozens or hundreds of single-owner sites, clicking through each one in the admin centre is too slow. PowerShell's Add-SPOUser cmdlet (with the -Group Owners parameter) can batch-add a fallback admin account as a secondary owner across an exported URL list. It is a reasonable interim fix - but each site still needs a proper secondary owner assigned once the compliance flag is cleared.
Building the two-owner rule into your governance process
Remediation clears the backlog. Governance prevents it from returning.
The most effective change is at provisioning. If site creation in your tenant goes through a request process (a Power Platform form, a Teams tab, or any ticketing system), add a required field for a second owner at the point of creation. The site does not get created until two names are provided.
For tenants where self-service site creation is enabled, the admin centre now includes inactive site policies that can flag sites with governance issues. Pairing this with a quarterly site ownership review, rather than a once-a-year audit, surfaces single-owner drift before it compounds. That cadence also catches sites where one of the two owners has since left, quietly dropping the count back to one.
The broader point is that Microsoft's two-owner requirement is not an administrative nuisance: it is a reasonable baseline for any SharePoint environment where content has real business or regulatory value. The sites most at risk of becoming governance problems are the ones nobody is paying attention to. Requiring two owners is one of the lowest-cost ways to ensure someone always is.
Frequently Asked Questions
What is the SharePoint minimum site owner requirement?
Microsoft now requires every SharePoint Online site to have at least two owners. Sites with only a single owner receive notification prompts and may face enforcement action as the rollout continues. The requirement was announced via Microsoft 365 Message Centre notification MC1402118.
How do I find SharePoint sites with only one owner?
In the SharePoint admin centre, go to Sites > Active sites and review the administrator and owners columns. Sites showing only one owner are non-compliant. You can export the list to CSV and filter in Excel, or use PowerShell's Get-SPOSite cmdlet. Report Master also exports site ownership data as a filterable Excel report.
What happens if a SharePoint site has only one owner?
If the sole owner leaves the organisation, the site becomes ungoverned: access requests go unanswered, no one can modify permissions, and IT must intervene manually to regain control. Microsoft's two-owner requirement formalises this risk as a compliance concern and is moving toward active enforcement.