Denied access to upload to a current shared folder on Sharepoint

Question

Hi all,

Suddenly, we are unable to upload a file to a shared folder. This shared folder has no issues; we can open and access files within it. However, when trying to upload a new file to the folder, access is denied.

This denied access is across all users, including the admin. Again, we can see and access the shared folder, but cannot upload files to it.

Storage is not full

User access has not been changed by the admin

We contacted Microsoft a few times, but there has still been no response from them. Any advise woudl be helpful. Thanks

Answer 1

Hi @Jhady Rios, 

Thank you for reaching out. It appears that the SharePoint site has entered a restricted state, preventing file uploads for all users, including administrators. This behavior typically indicates a site-level or tenant-level lock rather than an issue with individual permissions. 

Please find the following troubleshooting procedures to identify the underlying cause. You may provide the results of these checks to the support team to facilitate a more efficient resolution when reaching out for further assistance. 

1/ Verify site collection lock state. 

A site may be set to a ReadOnly state at the collection level, which overrides standard user permissions. You can verify and potentially resolve this using the SharePoint Online Management Shell: 

• To check the current state: Get-SPOSite -Identity <SiteURL> | Select LockState 
• To remove the lock: Set-SPOSite -Identity <SiteURL> -LockState Unlock 

Kindly refer to the article for more details: Lock and unlock sites - SharePoint in Microsoft 365 | Microsoft Learn 

2/ Confirm whether the tenant is out of storage. 

When SharePoint Online storage is exhausted, sites can be placed in read‑only mode and changes can’t be saved until storage is freed or increased. 

• Check total SharePoint storage usage in the Microsoft 365/SharePoint admin experience. 
• If you suspect the quota view/allocation is incorrect, Microsoft provides an admin diagnostic for tenant storage.
• Please consult the following article for the necessary steps: SharePoint in Microsoft 365 Out of Storage Space - SharePoint | Microsoft Learn

3/ Check for site closure / lifecycle policy. 

One frequent reason for the message This site is read-only at the site collection administrator’s request is that the site was closed by a policy and set to read-only.  If your org uses lifecycle/retention governance, verify whether the site has been marked “closed/archived” and needs to be reopened via the applicable policy/admin workflow. 

4/ Run the built-in admin diagnostics

Your IT admin can run diagnostics from Help & support to validate common “locked/read‑only” scenarios and (in some cases) attempt remediation:

• Run Tests: Locked Site (for read‑only/locked site errors) 
• Run Tests: Tenant Storage (for storage quota allocation/issues) 
• Kindly refer to the official article: SharePoint or OneDrive read-only error messages - SharePoint | Microsoft Learn 

While the aforementioned steps address the most common administrative causes, certain underlying infrastructure limitations or backend synchronization errors can only be resolved by a SharePoint Support Agent. There are instances where a site collection becomes restricted due to tenant-level throttling or a database-level integrity flag that is not visible or adjustable through the standard Admin Center or PowerShell. In such cases, specialized internal tools are required to reset the site's status and restore full write access.

To ensure your case progresses efficiently, please share the support ticket number from the Microsoft 365 Admin Center via the private message I have just initiated. Providing this information allows me to see the case assignment, monitor its status, and ensure an accurate reflection of tried troubleshooting data for the support team.
I look forward to receiving these details to assist in the oversight of this resolution.

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Answer 2

Use the following checks and fixes in order, focusing on permissions and site features, since all users (including admin) suddenly lost upload ability but can still read existing content.

1. Verify users still have edit/contribute permissions on the library/folder
   • Go to the affected SharePoint site → open the document library → select the folder → Manage access / Advanced permissions.
   • Confirm that the affected users/groups (including admin) have a permission level that includes Add Items (for example, Edit, Contribute, or higher).
   • If permissions look correct but uploads still fail, remove one affected user from the site and re‑grant access to the folder or site, then test again. This is the recommended fix when a user can open a shared link but gets access issues on operations like upload.
2. Check for “Limited-access user permission lockdown mode” being enabled
   If this site collection feature was recently enabled or changed, it can cause access-denied behavior on shared folders even when users can still open existing files. Symptoms that match your case:
   • Users can access the shared folder and its files.
   • When they try to perform certain operations (like upload or access items that rely on limited access), they get Access Denied.
   Cause:
   • When a folder is shared with users who do not have access to the parent, SharePoint uses Limited Access on parent items so they can work in that folder.
   • If Limited-access user permission lockdown mode is enabled, those limited-access permissions no longer work correctly, and users can be blocked from operations in that folder.
   Fix / workaround options:
   • As a site collection admin, go to Site settings → Site collection features and check whether Limited-access user permission lockdown mode is activated.
   • If the site does not require this feature (for example, for publishing), deactivate/disable it.
   • Alternatively, instead of sharing only the folder, grant users access at the site or library level so they no longer rely on Limited Access.
3. Confirm users are accessing with the correct account
   • If users open the shared folder with a different account than the one that was granted permissions, they can see some content via cached access but fail on operations like upload.
   • Have users sign out of all accounts in the browser, sign in only with the intended Microsoft 365 account, and try again.
4. If a specific user still cannot upload after the above
   • Remove that user from the site (and any sharing links), then re-share the folder or site with them. This is the documented fix when a user cannot use a shared link correctly even though permissions appear granted.

If the problem started recently and coincides with any admin changes (enabling information barriers, changing sharing policies, or enabling lockdown mode), revert or adjust those changes and test again.

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References:

• "Access Denied" error when trying to access a shared folder
• Access Denied or You need permission errors in SharePoint Online and OneDrive
• Unable to access SharePoint Online
• Resolve file upload errors in Microsoft Forms