SharePoint 2003: User can not be added to the site - “Cannot add the user because a user with that name already exists”

Often we come across issue when a user in SharePoint 2003 site cannot be added as a member of the site. The error that you encounter while adding the user is : “Cannot add the user because a user with that name already exists”.

However when you go through the list of users of the site, you cannot find this user. Neither he has got access to the site.

This issue generally occurs when you have changed the user’s account name in active directory. For example if you have a user with account domain\oldID with access to http://sitecollection. Now you have changed the account of the user in AD from domain\oldID to domain\newID. When the user now tries to access http://sitecollection, he gets “Access Denied”. On the other hand if the administrator tries to add user’s new account domain\newID to the site collection, following error is encountered: “Cannot add the user because a user with that name already exists”.

To fix this issue you need to delete user from site collection user list. So open the link http://<sitecollection>/_layouts/1033/Siteusrs.aspx . Replace your site collection path between <>.

Here you will see all the users in site collection. Identify your user’s ID from the list, and delete him/her. Now you can add the new account without any error.

You can also navigate to the above page: Site Settings > Go to Site Administration(Administrator Section) > View site collection user information (Site Collection Administration)

Please note that this fix is only applicable on SharePoint 2003