Thanks for your reply. In last mail, I have mentioned ldap API's used in my code. After all API call, am checking the return value. If it is success, then only am going for next api call, otherwise I will return from that point. In that crash scenario, ldap_start_tls_s() returned LDAP_SUCCESS, but it crashed inside ldap_sasl_interactive_bind_s(). That is why, I suspected ldap_start_tls_s() has corrupted the handle.