Set PeoplePicker via PowerShell, multiple domains.
PowerShell is much, much easier than the old stsadm.
To see the present settings:
$wa = Get-SPWebApplication -Identity https://your.website.something
$wa.PeoplePickerSettings.SearchActiveDirectoryDomains
—–
$wa = Get-SPWebApplication -Identity https://your.website.something
$ad = New-Object Microsoft.SharePoint.Administration.SPPeoplePickerSearchActiveDirectoryDomain
$ad.DomainName = “domainA.com”
$ad.IsForest = $true
$wa.PeoplePickerSettings.SearchActiveDirectoryDomains.Add($ad)
$a1 = New-Object Microsoft.SharePoint.Administration.SPPeoplePickerSearchActiveDirectoryDomain
$a1.DomainName = “domainB.com”
$a1.IsForest = $true
$wa.PeoplePickerSettings.SearchActiveDirectoryDomains.Add($a1)
$wa.Update()