Need more info on Azure Access Control Service (ACS) usage being retired for SharePoint

Question

Hi,

We have few Apps Registered and we follow the instructions given in this link to grant SharePoint permissions to them

https://piyushksingh.com/2018/12/26/register-app-in-sharepoint/

But I get a message saying - "Starting April 2, 2026, Azure Access Control service (ACS) usage will be retired for SharePoint in Microsoft 365 and users will no longer be able to create or use Azure ACS principals to access SharePoint'.

Does this mean , we can no longer use this way to access SharePoint documents via the custom app? what are the alternatives, please?

Regards,

Ash

Answer 1

Hello @Nanjappa, Ashwini, 

Thank you for posting your valuable question on Microsoft Q&A forum.   

I reviewed the official Microsoft announcement regarding the retirement of Azure Access Control Services (ACS) for SharePoint Online, and I’d like to provide clarification on what this means for your current apps and how to proceed. 

Microsoft has confirmed that Azure ACS is being fully retired for SharePoint Online. This includes the legacy app model that uses AppRegNew.aspx, AppInv.aspx, and ACS-issued client IDs/secrets. As part of this retirement: 

• Azure ACS will no longer work for new Microsoft 365 tenants as of November 1, 2024.  
• ACS will be fully retired for all existing tenants on April 2, 2026, and there will be no option to extend or continue using ACS beyond this date.  

This means that after April 2, 2026, applications that rely on ACS-including those registered using the method described in the documentation-will no longer be able to authenticate to SharePoint Online. 

Microsoft is strongly recommending that all customers transition to Microsoft Entra ID (formerly Azure AD) for authentication and authorization. Entra ID provides modern OAuth 2.0-based authentication and supports Microsoft Graph as well as SharePoint Online REST APIs. According to the announcement: 

For authoritative guidance on migrating your SharePoint Add‑In–based solutions to modern authentication and supported extensibility models, you can refer to Microsoft’s official article: Modernizing your SharePoint Add-In model implementations in Microsoft 365 | Microsoft Learn.

You can also check this resource about common questions about this retirement : SharePoint Add-Ins and Azure ACS retirement FAQ | Microsoft Learn 

Please don't hesitate to leave a comment if you need any further assistance. Thank you again for reaching out! 

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Answer 2

As of April 2, 2026, the Azure Access Control Service (ACS) will be fully retired for SharePoint Online, which means you will no longer be able to create or use Azure ACS principals to access SharePoint. This affects all custom applications that rely on ACS for authentication and authorization.

To continue accessing SharePoint documents via your custom apps, you should transition to using Microsoft Entra ID (formerly Azure Active Directory). This modern authentication method is recommended for better security and integration with other Microsoft 365 services. You can follow the guidance provided in the Microsoft documentation to migrate your applications from ACS to Entra ID.

For more information on how to migrate your applications and the steps involved, you can refer to the relevant articles on the Microsoft documentation site.

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References:

• Azure ACS retirement in Microsoft 365
• Accessing SharePoint using an application context, also known as app-only