After adding ADFS authentication to out environment we ran into an issue where users could add Active Directory or ADFS users accounts when granting permissions. Because we have both NTLM and ADFS enabled on the web application the would see both versions of the account.
We wanted to prevent them from being able to see both accounts from within a people picker, because users have no permissions and are unable to authenticate using NTLM (we use it just so search can crawl the farm) then we want to remove that option.
The solution to this problem was found here. These details the powershell commands to hide the Active Directory authentication provider and prevent it from showing up in the people picker. From within the SharePoint 2013 Management Shell:
$cpm = Get-SPClaimProviderManager $ad = get-spclaimprovider -identity "AD" $ad.IsVisible = $false $cpm.Update()
After running the powershell commands the Active Directory selection will not longer present itself as a selection: