CSOM Returns Unknown Site Users Like SLinkClaim

The CSOM (Client-Side Object Model) API returns multiple "unknown" site users, such as those with titles like SLinkClaim, due to how SharePoint handles claims-based authentication. The SLinkClaim is a type of identifier used by SharePoint to represent users who have been authenticated through claims-based identity providers, but for whom SharePoint does not have a corresponding user profile or information. This can occur when users are added to a site but do not have a fully recognized identity within the SharePoint environment.

The SiteUser object in CSOM represents a user in the SharePoint site. It encapsulates properties related to the user, such as their ID, login name, and display name. However, if the user is not fully recognized (like those represented by SLinkClaim), the object may not contain complete information, leading to the appearance of these "unknown" users.

In summary, the presence of SLinkClaim users indicates that the system recognizes the claim but lacks complete user profile data, which is why they are shown as unknown in the CSOM API results.

Hi @Dinesh,

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Based on your description, from my research, this behavior occurs because SharePoint uses claims-based authentication.

When an identity is authenticated through a claim's provider such as Azure AD or a federated directory, SharePoint creates an internal representation of that identity. When a claim can’t be mapped to a recognized user profile, SharePoint creates an internal identity with a placeholder like SLinkClaim.<GUID> and sometimes tagged as Guest Contributor. These entries usually appear for external or guest users who accessed the site through sharing links or weren’t fully provisioned.

The SiteUser object in CSOM corresponds to an entry in the User Information List of a SharePoint site collection. It represents any identity that has interacted with or been granted permissions on the site.

While Microsoft does not have an article specifically addressing SiteUser, I found an external resource that explains it in depth, feel free to review it for additional insights.

Note: Microsoft is providing this information as a convenience to you. These sites are not controlled by Microsoft, and Microsoft cannot make any representations regarding the quality, safety, or suitability of any software or information found there. Please ensure that you fully understand the risks before using any suggestions from the above link.

You can also find examples related to SiteUser in this Microsoft article on basic operations using sharepoint SCOM API here.

Regarding SLinkClaim, it is an internal identifier used by SharePoint for sharing link claims. These are special claim tokens created when someone uses a sharing link (anonymous or guest link) instead of signing in with a standard account.

For more details on claims-based identity, you can refer to this Microsoft article here.

I hope this helps.

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