Directory cleanup requirements . You may need to correct some attribute values in your on-premises directory. Common problems ...

Directory cleanup requirements. You may need to correct some attribute values in your on-premises directory. Common problems that need to be corrected are duplicate SMTP addresses, duplicate UPNs, or empty display names. The %BRAND_IDFIX% DirSync Error Remediation Tool can help you identify and correct these types of problems. To learn more, see Prepare directory attributes for synchronization with %BRAND_OFFICE_365_SHORT% by using the %BRAND_IDFIX% tool.