A particular user (Travel request Approver) has more than one user account in the active directory, which is causing confusion to end users, often.
So, the user wants to get rid of this issue, wants to delete the account from Active directory. His account got deleted from AD, we (SharePoint Admin) team ran the FULL profile import, but still the issue exists! end users seeing the approver’s name which got deleted from AD.
Hmm… The problem is: People picker gets the entries NOT only from AD. But from the user list of the site collection also. In this case, user’s ID is already added in the site, and People picker displays that!
In order to get rid of this issue: Delete the user from user information list, That is from: Site Actions >> Site Settings >> People and Groups >> All People (Shortcut: https://sharepoint.company.com/_catalogs/users/simple.aspx
In SharePoint 2010: /_layouts/people.aspx?MembershipGroupId=0 )
If you want cleanup user information list in bulk, refer my another article: Delete Users and Clean up User Information List