How to Index an Attribute in Active Directory:
- On your schema master go to Start --> Run and type in “regsvr32 schmmgmt.dll” (without the quotes), then press enter
- Open MMC and add the Active Directory Schema snapin
- In the console tree, click Attributes
- In the details pane, right-click the attribute that you want to index, and then click Properties
- Check the box Index this attribute in the Active Directory
- Click Apply, then Ok to apply changes