SharePoint sites read-only because storage is full
When total SharePoint storage in a Microsoft 365 tenant goes over the tenant's quota, Microsoft can put its sites into read-only mode: users can still open and read content, but they cannot add files or save changes. Microsoft's troubleshooting article for tenants out of storage space describes the email an administrator receives, the quota formula, and the three ways out: buy more storage, archive inactive content, or delete content you no longer need.
This page covers the exact messages, why a tenant ends up over, why buying storage does not always unlock it straight away, and how to get under quota without buying. It is written for an administrator looking at the lock right now.
The messages you will see
| Where | Message | Source |
|---|---|---|
| Email to Global and SharePoint admins | "SharePoint Online is out of storage space. Sites are in read-only mode and changes can't be saved." | Microsoft Learn |
| Email to Global and SharePoint admins | "There is not enough storage space on SharePoint Online. Your storage is full. You can buy more storage or use Microsoft 365 Archive to free up storage space without deleting any data." | Microsoft Learn |
| Banner shown to users | "Your organization's storage is full. SharePoint sites are read-only right now. Contact your IT department for more info." | Reported by administrators |
| SharePoint sites in a locked tenant | "Tenant sites are in read-only right now" | Microsoft Q&A |
| OneDrive in a locked tenant | "Your organization's storage is full. Your OneDrive is read-only right now." | Microsoft Q&A |
A different set of messages appears when a single OneDrive goes over its own quota, such as "This site has exceeded its maximum file storage limit" and "Unable to create new file. Site quota is full." That is a per-user licence quota and is a separate problem. Microsoft's article on it says so explicitly and points tenant-wide storage problems to the out-of-storage article above. For the per-user case, see OneDrive quota enforcement.
Why the tenant is over quota
Microsoft's article gives the formula: the SharePoint storage quota for a non-education organisation is 1 TB plus 10 GB per licence for the eligible plan, plus any Microsoft 365 Extra File Storage add-ons you have bought. A tenant is out of storage if total SharePoint usage exceeds that figure.
Two details explain most surprises:
- Removing licences lowers the quota. Every licence you remove takes 10 GB with it, so a tenant can drop below its usage without anyone adding a file. SharePoint storage quota dropped walks through the formula and the licences that count.
- Archived data does not count. Microsoft states that data in Microsoft 365 Archive is held in SharePoint but does not count toward the active storage quota.
Is Microsoft locking over-quota tenants now?
Read-only mode as the consequence of being over quota is documented. What looks new is how many administrators report seeing it. Practitioners say tenants that sat over their limit for months with no consequence are now being locked, and some describe an admin centre banner giving a deadline to buy storage.
What we can say from Microsoft's own material:
- Microsoft documents read-only mode as the state a tenant over quota can be put into.
- Microsoft does not publish a grace period, so there is no safe number of days to plan around.
- Nothing in the articles we checked says data is deleted because a tenant is over its SharePoint quota. That differs from unlicensed OneDrive accounts, which Microsoft archives and eventually deletes on a fixed schedule.
- The Message Center posts about storage this year that we have read cover OneDrive per-user quotas, pay-as-you-go billing and the legacy OneDrive allowance. We have not found one that announces a date for locking tenants over their SharePoint quota. See the November storage changes.
Check your own Message Center and the SharePoint admin center banner, because some notices go only to affected tenants and are not in the public archive.
You bought storage and it is still read-only
This is the case administrators describe most often, and Microsoft's documentation says little about it. What is documented:
- The usage figure lags. In the SharePoint admin center the storage used "doesn't include changes made within the last 24-48 hours", so the figure you are acting on can be a day or two behind.
- The purchase route matters. If the subscription was bought through Volume Licensing or a Cloud Solution Provider, you cannot buy Office 365 Extra File Storage directly from Microsoft. Contact your representative or partner.
- No free-space threshold is published. The articles we checked give no minimum headroom and no time for the lock to clear after a purchase.
What administrators report in community discussions, which is not Microsoft guidance: sites staying read-only for 24 to 48 hours after the storage appears, some for much longer, and tenants that had bought barely any headroom staying locked. Usage keeps growing while the figure lags, so buy with margin and not to the exact byte.
Unlocking sites by hand is not a reliable fix for a tenant-wide lock. In one Microsoft Q&A case, a tenant showing 1.02 GB used of 1.27 TB was read-only across SharePoint and OneDrive, unlocking sites with Set-SPOSite -LockState Unlock did not clear it, and the advice was to open a support ticket. To see where each site stands, run:
Get-SPOSite -Limit All | Select Url, LockState, StorageQuota, StorageUsageCurrent
If the admin center shows the new quota, usage is comfortably under it and the sites are still read-only after a couple of days, open a support case with those figures and ask whether a service incident applies.
Pay-as-you-go as the way out
Microsoft 365 SharePoint Storage is a pay-as-you-go service that lets a tenant keep using SharePoint beyond its quota, billed on the overage. It is in public preview for commercial tenants, with general availability from early November. While a tenant is enrolled, it is treated as within quota and the quota emails and admin center banners stop. It needs an Azure subscription and resource group, and a SharePoint Administrator or Global Administrator. It is not available to education, GCC or Microsoft 365 operated by 21Vianet tenants. If you disconnect while the tenant is over quota, enforcement resumes immediately. The timing and the details are in the November storage changes.
Getting under quota without buying
Most tenants are carrying space they do not know about. In rough order of size:
- Version history. Often a large hidden consumer. Setting automatic version trimming and clearing existing versions can free a lot, though the new figure can take hours or days to appear. SharePoint version history storage covers it.
- The two-stage recycle bin. Deleted files count against the quota until they are gone from both stages. See the SharePoint recycle bin.
- The Preservation Hold Library. It grows quietly under retention policies. See clearing the Preservation Hold Library.
- Departed users' content. Removing a licence takes 10 GB off the quota while their data stays. See SharePoint storage full or almost full for the full list and why deleting often frees nothing.
- Large content inside sites that look small. A site collection's total includes its subsites, so one large subsite can sit inside a site that looks modest. See what is using your SharePoint storage breaks usage down by site, library and file, and the free SharePoint Storage Explorer reports it down to the folder.
Archiving inactive content
Microsoft's article names archiving inactive content that should be retained as one of the three ways out, and it points to Microsoft 365 Archive. The reason archiving works is that it moves bytes out of the active quota.
Squirrel is the third-party route. It archives inactive files from SharePoint document libraries into your own Azure storage and leaves a pointer page in SharePoint, so a user restores a file in one click, with no restore fee from Squirrel. Archiving reduces bytes, not item counts, so it does nothing for a limit on the number of items.
One practical point if you are already locked: archiving writes a pointer page into the library, and a read-only site does not allow writes. Plan to archive before a site is locked, or once you have write access back, and ask us before assuming it will run on a locked site.
Frequently asked questions
What does read-only mean for SharePoint users?
Users can still open and read content, but they cannot add files or save changes. Microsoft's email says: "Sites are in read-only mode and changes can't be saved."
Will Microsoft delete my data if the tenant stays over quota?
Nothing in Microsoft's articles that we checked says SharePoint data is deleted for being over the tenant quota, and Microsoft publishes no grace period. Do not treat the absence of a published deadline as safety: once the lock is applied, writes stop.
Will Microsoft bill me automatically for the overage?
Microsoft does not automatically bill for exceeding the quota. Extra storage is something you buy, as the Extra File Storage add-on or through the opt-in pay-as-you-go service.
How long does it take to unlock after I buy storage?
Microsoft does not publish a time. The admin center usage figure can be 24 to 48 hours behind, and administrators report the lock lasting 24 to 48 hours or longer after the storage appears.
Can I unlock the sites with PowerShell?
Not reliably. In a Microsoft Q&A case of a tenant-wide lock, unlocking sites with Set-SPOSite -LockState Unlock did not clear the read-only state, and the advice was to open a support ticket.
Does Microsoft 365 Archive count toward the quota?
No. Microsoft states that archived data is held in SharePoint but does not count toward the active storage quota.
Is this the same as the OneDrive read-only message?
Not exactly. A single OneDrive over its own quota is a per-user licence issue. A tenant out of SharePoint storage can show the OneDrive message "Your organization's storage is full" for every account.
Related reading
- SharePoint storage full or almost full - why deleting does not free space, and the six places it hides.
- SharePoint storage quota dropped - the pooled formula and the licences that count.
- SharePoint and OneDrive storage changes, November 2026 - pay-as-you-go billing and the OneDrive allowance.
- OneDrive quota enforcement (MC1310684) - the per-user read-only state.
- Find over-quota OneDrives and SharePoint sites - PowerShell for the affected list.
- SharePoint Online limits - the quota formula and the other hard limits.
Mark Smith co-founded SmiKar Software in 2015 and has spent the past decade helping organisations solve Microsoft 365 data management challenges. He works with the SmiKar team to build solutions for SharePoint archiving, storage optimisation, governance and compliance, supporting customers from growing businesses through to Fortune 500 enterprises.
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