You inherit a tenant with 600 sites. Nobody can tell you, off the top of their head, which of those sites still has a living, working owner attached to it. That gap is the one this guide closes.
Ownership is one of the quietest failure points in SharePoint governance. A site does not stop working when its owner leaves the company. Files stay accessible, permissions stay in place, and nothing visibly breaks. What breaks is accountability: nobody can approve a new access request, decide whether the site should be archived, or answer for what is stored there when an audit asks. This guide covers how to find every site missing an owner, and how to close the gap methodically rather than one admin-centre click at a time.
Why This Is Easy to Miss
Self-service site creation is convenient, and that convenience has a cost. When a user creates a team site or a communication site, they become the sole owner by default. Unless someone deliberately adds a second owner, that site is exactly one resignation away from having none at all. Multiply that across a few years of organic growth and a mid-size tenant can easily be carrying dozens of ownerless sites without a single alert ever firing.
Sites connected to a Microsoft 365 group have a related but distinct problem: group ownership and site ownership can drift apart. A group can lose its last owner in Entra ID while the underlying SharePoint site collection administrator field still shows a name, technically populated but pointing at an account that no longer has group management rights.
What Counts as "No Owner" in Practice
Before you start exporting reports, it helps to define the categories you are actually hunting for, since "no owner" covers a few different situations:
- Truly empty: the owner or site collection administrator field is blank.
- Ghost owner: a name is listed, but the account has been disabled or removed from the directory.
- Single point of failure: exactly one active owner exists, with no backup.
- Role mismatch: the listed owner has left the team or department the site actually serves, even though the account is still active elsewhere in the tenant.
All four are worth catching, though the first two are the most urgent, since they represent sites where literally nobody with authority can act today.
Step 1: Check What the Admin Centre Shows You
Start in the Microsoft 365 admin centre. Under Admin centres, open SharePoint, then Sites, then Active sites. Selecting an individual site opens a details panel showing the listed owner or site collection administrators. This works fine for spot-checking a handful of sites, but it does not give you a single filterable view across a large tenant, since you would need to open each site one at a time.
When the admin centre view is enough
If your tenant has fewer than about thirty sites, clicking through each one individually is realistic. Beyond that, it becomes the kind of task that gets started and never finished, which is exactly how ownerless sites accumulate in the first place.
Step 2: Export a Full Site Inventory
For anything larger than a small tenant, a bulk export beats manual clicking. Open ShareMaster, sign in with an account that has SharePoint admin permissions, and run a site inventory export in Report Master. The resulting Excel workbook lists every site in the tenant with its current owner, storage used, and last activity date on one sheet, which turns a click-through exercise into a five-minute filter.
Step 3: Filter for the Gaps
With the inventory in hand, filter the Owner column for blank cells first. That gives you the truly empty cases. Next, cross-reference the remaining owner names against your directory or HR system to catch ghost owners, accounts that are technically listed but no longer active in the organisation. This second pass takes longer than the blank-cell filter but usually turns up more sites than the first pass alone.
| Filter pass | What it catches | Typical effort |
|---|---|---|
| Blank Owner column | Sites with no owner listed at all | Minutes, one filter |
| Owner cross-referenced against directory | Ghost owners: listed but no longer active | Longer, needs a directory export to compare against |
| Single-owner sites flagged manually | Sites at risk of becoming ownerless next | A follow-up pass once the urgent gaps are closed |
Step 4: Prioritise Before You Start Assigning Owners
Not every flagged site deserves the same urgency. Sort your filtered list by storage used and last activity together. A site with recent uploads and no owner needs attention this week. A site with no owner and no activity in over a year is a better candidate for an archive-or-delete conversation than for hunting down a new owner who may not even remember the site exists.
- Active, unowned sites: assign a new owner immediately.
- Active, single-owner sites: add a second owner as a safeguard.
- Dormant, unowned sites: route to an archive or deletion decision instead of an ownership fix.
Step 5: Assign the Owners
For a standalone site, open the site in the SharePoint admin centre, select Permissions, and add a new site collection administrator. For a group-connected site, add the new owner through the Microsoft 365 admin centre's Groups panel instead, since the group owner list is what ultimately governs site-level administrative rights for that site type. Where your organisation uses a request or approval workflow for ownership changes, route the assignment through that process so there is a record of who approved it.
Step 6: Confirm the Fix
Run the Report Master site inventory export again once remediation is done. Compare the new Owner column against your original flagged list line by line. This closing pass matters because it is easy for an ownership change to be applied at the wrong level, added as a member instead of an owner, for instance, and the only reliable way to catch that is to check the export, not to trust that the change went through as intended.
Frequently Asked Questions
Why does a SharePoint site end up with no owner?
Most commonly, the original owner leaves the organisation or changes roles and nobody reassigns the site before their account is disabled. Self-service site creation is another common cause, since the creator becomes the sole owner automatically.
Can I tell which sites lack an owner from the SharePoint admin centre alone?
You can check individual sites one at a time through the site details panel, but there is no single filterable list of every ownerless site across a large tenant. Exporting a full inventory is faster once a tenant has more than a handful of sites.
What happens if a site is left without any owner indefinitely?
The site keeps functioning for existing members, but nobody can approve new access requests, review permissions, or make governance decisions about its future.
Should every SharePoint site have more than one owner?
A second owner is widely recommended as good governance practice, since it removes the single point of failure created when the sole owner leaves or becomes unreachable.
See what Report Master exports
For the underlying rules Microsoft applies to site ownership, including the newly enforced minimum of two owners, see the site ownership requirements reference.