private static bool UserExistsInAD(string sid) { ADSessionSettings sessionSettings = ADSessionSettings.FromRootOrgScopeSet(); IRecipientSession tenantOrRootOrgRecipientSession = DirectorySessionFactory.Default.GetTenantOrRootOrgRecipientSession(true, ConsistencyMode.IgnoreInvalid, sessionSettings, 103, "UserExistsInAD", "f:\\15.00.1497\\sources\\dev\\data\\src\\storage\\Auditing\\AdminAuditExternalAccessDeterminer.cs"); PropertyDefinition[] properties = new PropertyDefinition[] { ADMailboxRecipientSchema.Sid }; ADRawEntry adrawEntry = tenantOrRootOrgRecipientSession.FindUserBySid(new SecurityIdentifier(sid), properties); return(adrawEntry != null); }