So I find this issue comes about a lot of the time for female users, reasons being is when they get married, they take the mans surname. So when their name changes in AD, this doesn’t automatically reflect the same in SharePoint.

When Active Directory Syncs with SharePoint User Profile Service, it also does a sync in parallel with the User Information List (UIL). When new users are added or modified, these users will be added to the UIL. Unfortunately, when user names are changed, this doesn’t always update the UIL and therefore creates a second account for the new updated surname account.

To fix this, we have to merge the accounts together and delete the old one. Without carrying this out, you will probably notice that SharePont still uses your old account which you’ll notice in the top right corner of SharePoint.

So firstly you can check the UIL by going to the url below

http://YOURSITEHERE/_catalogs/users/simple.aspx

Following that, you’ll get a list of users that are in SharePoint, you can also find the users by going to Site Settings, People and Groups. Change the URL at the end to look at MembershipGroupId=0, the full URL can be seen below using my own site.

http://sharepoint-oc/_layouts/15/start.aspx#/_layouts/15/people.aspx?MembershipGroupId=0

From here, you’ll notice two accounts for one user, so we’ll need to merge these using PowerShell and then delete the old.

$user = Get-SPUser -Identity “CHIN\MDean” -Web “http://SharePoint-OC/”
Move-SPUser -Identity $user -NewAlias “CHIN\MTravis” -IgnoreSID

The script above moves your old account to the new account with the new surname. Including the permissions that were there.

Once Completed, go to the link below again and delete the old user.

http://sharepoint-oc/_layouts/15/start.aspx#/_layouts/15/people.aspx?MembershipGroupId=0

It might require the user to log out and in for the update however, I’ve seen it just change without needing it sometimes.