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 site ownership policy is built to stop exactly that from happening.
Is there a Microsoft rule that every site needs two owners?
No. You will read that "SharePoint now requires two owners", usually on a university or company IT page, but those pages describe a policy that organisation switched on. Microsoft has not imposed a tenant-wide minimum. What it provides is the site ownership policy, part of SharePoint Advanced Management, where a SharePoint administrator decides the minimum number of owners or site admins, which sites the policy covers, and what happens when a site falls short.
Set the minimum to two and the policy identifies every single-owner site in its scope. In simulation mode it runs once and produces a report. In active mode it runs monthly, reports, and emails the recipients you choose: the current owners, the current site admins, the managers of owners who have left, or recently active site members who can accept ownership.
Enforcement is deliberately gentle. A site that still has one owner is only ever notified: three monthly emails, then a three-month pause, then the emails resume. Read-only and archive apply only to sites with no owner at all, and only if you chose one of those enforcement actions when you created the policy.
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. A two-owner minimum 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
If your tenant has SharePoint Advanced Management, the quickest list is a site ownership policy in simulation mode with the minimum set to two. It runs once, notifies nobody, and its downloadable report gives the owner and admin counts and email addresses for every site below the minimum.
Without it, 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.
Once you have the single-owner list, Report Master's Security Matrix shows who holds which permissions on each of those sites, so you can pick a sensible second owner without writing any scripts. The guide to finding SharePoint sites without an owner walks through the steps.
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 policy stops flagging it.
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, a site ownership policy in active mode does this check for you every month. Without one, a quarterly site ownership review, rather than a once-a-year audit, surfaces single-owner drift before it compounds. Either way you also catch sites where one of the two owners has since left, quietly dropping the count back to one.
The broader point is that a two-owner minimum 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?
There is no tenant-wide rule from Microsoft. A minimum owner count is something an admin sets in a SharePoint site ownership policy, part of SharePoint Advanced Management. With the minimum set to two, the policy runs monthly in active mode, reports every site below it and emails the people you choose. Sites with one owner are only notified; read-only and archive apply only to sites with no owner.
How do I find SharePoint sites with only one owner?
With SharePoint Advanced Management, run a site ownership policy in simulation mode with the minimum set to two: it reports every site below that count without notifying anyone. Without it, go to Sites > Active sites in the SharePoint admin centre and review the administrator and owners columns. You can export the list to CSV and filter in Excel, or use PowerShell's Get-SPOSite cmdlet. Report Master's Security Matrix then shows who else holds permissions on a given site, which helps when choosing its second owner.
What happens if a SharePoint site has only one owner?
Nothing, unless a site ownership policy covers it. A policy with a minimum of two emails the owner, and any other recipients you configured, asking for a second owner. It never blocks a site that still has one owner. The practical risk is the sole owner leaving: access requests go unanswered and IT must step in to appoint someone.
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