Sometimes things get deleted. Ever since Microsoft added the Active Directory Recycle Bin its a lot easier to restore those objects. No need to do an authoritative restore from backup.

Enable the Active Directory Recycle Bin:

Enable-ADOptionalFeature "Recycle Bin Feature" -server $((Get-ADForest -Current LocalComputer).DomainNamingMaster) -scope ForestOrConfigurationSet -target $(Get-ADForest -Current LocalComputer)

List Deleted Objects:

Get-ADObject -filter {(isdeleted -eq $true) -and (name -ne "Deleted Objects")} -includeDeletedObjects -property * | format-list samAccountName,lastknownParent,DistinguishedName

Restore deleted object:

restore-adobject -identity <distinguishedname>

Restore multiple deleted objects (objects that have a name that starts with smith):

Get-ADObject -filter {(isdeleted -eq $true) -and (name -match "smith*")} -includeDeletedObjects -property * | restore-adobject